2023Activity reportProjectTeamCAGIRE
RNSR: 201120995C Research center Inria Centre at the University of Bordeaux
 In partnership with:CNRS, Université de Pau et des Pays de l'Adour
 Team name: Computational AGility for internal flows sImulations and compaRisons with Experiments
 In collaboration with:Laboratoire de mathématiques et de leurs applications (LMAP)
 Domain:Applied Mathematics, Computation and Simulation
 Theme:Numerical schemes and simulations
Keywords
Computer Science and Digital Science
 A6.1.1. Continuous Modeling (PDE, ODE)
 A6.2.1. Numerical analysis of PDE and ODE
 A6.2.7. High performance computing
 A6.5.2. Fluid mechanics
Other Research Topics and Application Domains
 B2. Health
 B4. Energy
 B4.2. Nuclear Energy Production
 B5.2.1. Road vehicles
 B5.2.3. Aviation
 B5.2.4. Aerospace
1 Team members, visitors, external collaborators
Research Scientists
 Rémi Manceau [Team leader, CNRS, Senior Researcher, HDR]
 Pascal Bruel [CNRS, Researcher, HDR]
 Vincent Perrier [INRIA, Researcher, HDR]
 Kevin Schmidmayer [INRIA, ISFP]
Faculty Member
 Jonathan Jung [LMAP, Associate Professor]
PostDoctoral Fellows
 Puneeth Bikkanahally Muni Reddy [UPPA, PostDoctoral Fellow]
 Martin David [UPPA, PostDoctoral Fellow, from Nov 2023]
PhD Students
 Anthony Bosco [UPPA]
 Esteban Coiffier [CEA]
 Alexis Ferre [CEA]
 Ibtissem Lannabi [LMAP]
 Jules Mazaleyrat [Safran HE, from Oct 2023]
 Mahitosh Mehta [UPPA, HDR]
 Corina Sanz Souhait [EDF, from Dec 2023]
 Romaric Simo Tamou [IFPEN]
Technical Staff
 Abderrahman Benkhalifa [UPPA, Engineer, from Oct 2023]
 Luca Cirrottola [INRIA, Engineer, from Feb 2023]
Administrative Assistant
 Fabienne Cuyollaa [INRIA, from Aug 2023]
2 Overall objectives
The projectteam CAGIRE is an interdisciplinary project, which brings together researchers with different backgrounds (applied mathematics and fluid mechanics), who elaborated a common vision of what should be the numerical simulation tools in fluid dynamics of tomorrow. The targeted fields of application are mainly those corresponding to the aeronautical/terrestrial transportation and energy production sectors, with particular attention paid to the issue of energy transition and the reduction of environmental impacts. This panel has been extended to medical applications recently, where numerical simulation plays an increasingly important role. Through our numerous industrial collaborations, we have been able to refine our vision of the future of numerical simulation, which is subject to ambitious industrial objectives, constant evolution of computing resources and increasingly present environmental constraints.
The flows under consideration involve many physical phenomena: they can be turbulent, compressible, multiphase, anisothermal. Even if these phenomena are not necessarily present at the same time, our strategy for developing models and numerical schemes must take them into account. Turbulence plays a central role insofar as it is a dimensioning constraint for CFD in most industrial configurations. It is indeed the comparison of the requirements in terms of scale of description, numerical accuracy and computational cost that guides the choice of physical models and numerical methods.
Because such flows are exhibiting a multiplicity of length and time scales resulting from complex interactions, their simulation is extremely challenging. Even though various simulation approaches are available and have significantly improved over time, none of them does satisfy all the needs encountered in industrial and environmental configurations. We consider that different methods will be useful in the future in different situations, or regions of the flow if combined in the same simulation, in order to benefit from their respective advantages wherever relevant, while mutually compensating for their limitations. For instance, for turbulent flows, it will thus lead to a description of turbulence at widely varying scales in the computational domain. The RANS1 method may cover regions where turbulence is sufficiently close to equilibrium, leaving to LES2 the regions where the RANS description is insufficient, leadind to a hybrid RANSLES approach. Similarly, for twophase flows, one of the greatest challenges is to be able to tackle simultaneous and dynamical modelling of the multiscale features and their transition, e.g., from cavitation pockets to tiny bubbles. The models and numerical methods must also be flexible enough to accurately represent all the abovementioned phenomena in complex geometries, with efficient and robust resolution algorithms to preserve an optimal computational cost. It is this flexibility and adaptability of models and numerical methods that we call “computational agility", which is in the title of the CAGIRE team: Computational AGility for internal flow sImulations and compaRisons with Experiments.
Therefore, the longterm objective of this project is to develop, validate, promote and transfer original and effective approaches for modeling and simulating generic flows representative of configurations encountered in applications, in various fields, such as of transportation, energy production and medicine. In order to progress in this direction, many building blocks have to be assembled, which motivates a variety of research topics described in the following sections and divided into four main research axes. The topics addressed, ranging from advanced physical modelling to highorder numerical discretization, require the multidisciplinary skills that constitute the CAGIRE projectteam:
 Turbulence modelling
 Highorder numerical methods and efficient algorithms
 Compressible and multiphase flows
 Analysis and simulation of turbulent flows and heat transfer
3 Research program
3.1 Turbulence modelling
In the “agile" simulation methods introduced above, a flexible representation of turbulence is essential: in the same simulation, depending on the regions of the flow, it is necessary to be able to switch from a finegrained to a coarsegrained representation of turbulence. Numerous methods, called hybrid RANS/LES, go in this direction, by associating LES and RANS. In order to ensure such a flexibility, it is preferable not to rely on a preliminary partition of the domain (the socalled zonal approach), but rather on a continuous transition from one model to the other (the socalled continuous approach).
Various questions then arise: how can we improve the RANS models so as to accurately represent most of the physical phenomena in order to avoid having to switch to LES in large regions; how to play on the terms of the models, and on which criteria, to switch from RANS to LES; how to improve the robustness of the method with respect to the choices made by the user (in particular the mesh). Our research work, described below, aims at answering these questions.
Today, even though the industrial demand for more accurate and robust RANS models is very significant, very few academic teams are active in this field (for instance, 118, 88, 60, 123), most of them being participants to the European ERCOFTAC SIG15 group of which we are an active member. In France, we collaborate or have recently collaborated with most of the teams, mainly in the industry (EDF, Dassault, PSA, SAFRAN) or applied research organizations (ONERA, CEA). The CAGIRE team is particularly renowned for its work on the interaction between turbulence and the wall by elliptic blending (EBRSM, 97, 101), and is solicited by these partners to improve the representation of complex effects on turbulence (buoyancy, conjugate heat transfer, adverse pressure gradients, impingement, etc.).
Concerning the development of original hybrid RANS/LES approaches, the main contributions in France are due to ONERA (ZDES 74 and PITM 71); IMF Toulouse in collaboration with the ECUADOR team of the Inria center of SophiaAntipolis (OES 66, 108) and CAGIRE (HTLES 100, 58, 80, 65). The originality of our work is twofold: (i) through temporal filtering, a formally consistent link is provided between the equations of motion and the hybridization method in order to reduce the level of empiricism, which is, for nonhomogeneous turbulence, along with the additive filter method 84, 57, one of only two methods capable of providing such a consistent framework; (ii) through the development of an active approach based on the Anisotropic Linear Forcing (ALF) 15 and an adaptive strategy that autonomously determines the LES zone and refines the mesh based on physical criteria 21, a new Continuous Embedded LES paradigm is proposed, which is a realisation of the agility concept at the center of our project.
3.2 Highorder numerical methods and efficient algorithms
When dealing with RANS models, a second order finite volume method is usually used. In our project, we aim at addressing hybrid RANS/LES models, which include some regions in which essentially unstationary processes are approximated in LES regions. This usually requires to use low dissipative high order numerical methods. If a consensus has emerged for years on second order finite volume methods for the approximation of RANS models, investigations are still ongoing on finding the high order method that would be the best suited with the compressible NavierStokes system.
As far as high order numerical methods are concerned, they are addressed at Inria essentially by the Atlantis, Makutu, Poems and Rapsodi teams for wavematter interaction problems, the Serena and Coffee projectteam on porous media, the Tonus team on plasma physics problems, and the Acumes, Gamma, Cardamom and Memphis teams for systems that are closer of ours (shallowwater or compressible Euler). As far as we know, only the Cardamom and Gamma teams are using high order methods with turbulence models, and we are the only one to aim at hybrid RANS/LES models with such methods.
Our objective is to develop a fast, stable and high order code for the discretization of compressible NavierStokes equations with turbulence models (Reynoldsstress RANS models and hybrid RANS/LES methods) on unstructured meshes. From a numerical point of view, this raises several questions: how to derive a stable numerical scheme for shocks without destroying the order of accuracy, how to derive stable boundary conditions, how to implement the method efficiently, how to invert the system if implicit methods are used?
Concerning aeronautical applications, several groups are working on discontinuous Galerkin methods: in Europe, some of the groups participated to the TILDA project 3 (DLR, ONERA, CERFACS, Imperial College, UCL, Cenaero, Dassault, U. of Bergamo). As far as we know, none of them considered Reynoldsstress RANS models or hybrid RANS/LES models. Worldwide, we believe the most active groups are the MIT group 4, or Ihme's group5 which is rather oriented on combustion. Concerning HPC for high order methods, we carefully follow the advances of the parallel numerical algorithm group at Virginia Tech, and also the work around PyFR at Imperial College. Both of these groups are considering imperative parallelism, whereas we have chosen to consider task based programming. Task based parallelism was considered in the SpECTRE code 95 based on the Charm++ framework, and within a European project6, based on IntelTBB, but only for hyperbolic systems whereas we wish to address the compressible NavierStokes system.
3.3 Compressible and multiphase flows
In this section, we are interested in two specific regimes of compressible flows: low Mach number flows and compressible multiphase flows.
Low Mach number flows (or low Froude for ShallowWater systems) are a singular limit, and therefore raise approximation problems. Two types of numerical problems are known: if convective time scales are considered, semiimplicit time integration is often preferred to explicit ones, because the acoustic CFL is very restrictive compared with the convective one in the low Mach number limit 75. The second numerical problem at low Mach number is an accuracy problem. The proposed fixes consist in changing the numerical flux either by centering the pressure 114 or are variant of the RoeTurkel fix 85. Over the last years, we have been more focused on the accuracy problem, but our major originality with respect to other groups is to be interested in the acoustic wave propagation in low Mach number flows, which may also raise problems as first remarked in 107.
Understanding and controlling complex and physically rich flows, such as unsteady multiphase compressible flows, are of great importance in various fields such as aeronautics, automotive, aerospace, nuclear energy, naval and also medicine. If we note the efforts established so far to partially respond to the problems linked to these flows, we also note major remaining challenges, particularly when different spatial and temporal scales or multiple physical phenomena, such as phase change, viscoelasticity or more generally interactions with solids, are to be considered. Good examples are cavitating flows such as the ones encountered around naval propellers where cavitation pockets form at the vicinity of the blades and lead to a turbulent bubbly flow in the wake 115. Or in biomedical applications such as in lithotripsy (treatment for kidney stones) 112 or, recently, histotripsy (noninvasive treatment for cancers) 94 where cavitation bubbles, induced by shock waves, laser energy deposit or highintensity focused ultrasound waves, violently collapse and interact with biomaterials. In this context, we aim to tackle the particularly challenging and ambitious modelling of these extremely complex multiphase compressible flows where numerous scientific and technical obstacles remain to be overcome. Among them, we could cite:
 The modelling of multiscale features including the simultaneous and dynamical computation of subgrid dynamics (inclusions such as bubbles or drops) and of resolved interfaces. The derivation of averaged compressible multiphase models is currently less active than in the 2000s, and only few teams are interested in such problems. Recent advances were made at RWTH 87, and also mostly in France at EDF R&D by J.M. Hérard or also by Bresch and Hillairet 68. This low interest in this type of challenging modeling and mathematical analysis was noticed in the review paper 117 as an obstacle for the improvement of numerical methods. Hence, the driving idea of this project to focus our efforts on the modeling of subscale phenomena, in particular by a stochastic process 111.
 The modelling of biomaterials under a fluidmechanics formulation including viscoelastic behaviour and realistic equations of state, and the modelling of bubbles containing simultaneously condensable and noncondensable gases. The simultaneous coupling of compressible, multicomponent flow models with viscoelastic solids and mass transfer will enable us, through simulations, to understand the fundamental physics taking place in several medical applications involving bubble dynamics 67. This will therefore fill the knowledge gap on the subject involving significant range of physical phenomena that are not well understood yet, and for which experiments often lack insight, and spatial and temporal resolution 64. This will potentially lead to significant improvements of the current and future medical treatments regarding their success rate, cost and safety.
3.4 Analysis and simulation of turbulent flows and heat transfer
The numerous discussions with our industrial partners make it possible to define configurations to carry out comparison between computations and experiments aimed at validating the fundamental developments described in the previous sections. Reciprocally, the targeted application fields play an important role in the definition of our research axes, by identifying the major phenomena to be taken into account. This section gathers applications which essentially deal with turbulent internal flows, most often with heat transfer.
Detailed data are required for a fine validation of the methods. In addition to the active participation and coorganizing of the SIG15 group of the ERCOFTAC network, which gives us access to various experimental or DNS data and enables us to carry out model and code benchmarking exercises with other European teams 96, 102, 63, 99, we generate experimental data ourselves when possible and develop collaborations with other research groups when necessary (ONERA, institute Pprime, CEA).
Historically, the scientific convergence between the team members that led to the development of our project and the creation of the CAGIRE projectteam in 2016 was based on scientific themes related to aeronautical combustion chambers (hence the term internal flows in the name of the team), with our industrial partners SAFRAN and Turbomeca (now SAFRANHelicopter Engines). If the scientific and application themes of the team are now much more diverse, these applications to aeronautical combustors are at the origin of the existence of the MAVERIC experimental facility, allowing the study of turbulent flows at low Mach number over multiperforated walls subjected to a coupling with acoustic waves, representative of the flows in combustors. This wind tunnel is thus complementary to those developed at ONERA, with which we collaborated 113 when it was necessary to add thermal measurements, within the framework of the European project SOPRANO.
4 Application domains
4.1 Aeronautics
Cagire is active in the field of aeronautics through the following activities:
 The combustion chamber wall: the modelling, the simulation and the experimentation of the flow around a multiperforated plate representative of a real combustion chamber wall have been focused on during the recent period. The continuous improvement of our inhouse test facility Maveric is also an important ingredient to produce our own experimental validation data for isothermal flows. For nonisothermal flows, our participation in the EU funded program Soprano gave us access to nonisothermal data produced by Onera. This activity is also included in the E2SUPPA project Asturies.
 The flow around airfoils: the modelling of the turbulent boundary layer has been for almost a century a key issue in the aeronautics industry. However, even the more advanced RANS models face difficulties in predicting the influence of pressure gradients on the development of the boundary layer. A main issue is the reliability of the modelling hypotheses, which is crucial for less conservative design. One of the technological barriers is the prediction of the flow in regimes close to the edge of the flight domain (stall, buffeting, unsteady loads) when the boundary layer is slowed down by an adverse pressure gradient. This was the subject of the CIFRE PhD thesis of Gustave Sporschill in collaboration with Dassault Aviation.
 Impinging jets: because of their high heat transfer efficiency, turbulent impinging jets are commonly used in a large variety of applications, and in particular blade cooling systems. Understanding the underlying physics of the mechanisms at play is of prime interest and is still an open question. Additionally, this configuration remains a challenging test case for turbulence models since it embraces many flow features despite a relatively simple geometry, and causes strong discrepancies between standard turbulence closures. Reynolds stress transport models have been shown to be promising candidates but still suffer from a lack of validation regarding this flow configuration. Such models are the subject of a collaboration with Onera and a starting collaboration with SAFRAN HE (CIFRE PhD thesis of Jules Mazaleyrat).
 Atmospheric reentry problem: When a body enters the atmosphere with a high velocity, its trajectory is mainly driven by the hypersonic flow surrounding the body. The integrity of the body is maintained by a shield that is progressively ablated. The sharp control of the motion is possible with a very good knowledge of the surrounding hypersonic flow and of its interaction with the ablated shield. Within the SEIGLE project, the team is involved in the simulation of the interaction of a droplet (representing the ablated body) and a hypersonic flow. In the Asturies project, the aim is to study the improvement on the shock/turbulence interaction by using advanced RANS models (secondmoment closure).
4.2 Energy
 The prediction of heat transfer in fluid and solid components is of major importance in power stations, in particular, nuclear power plants. Either for the thermohydraulics of the plenum or in the study of accidental scenarii, among others, the accurate estimation of wall heat transfer, mean temperatures and temperature fluctuations are necessary for the evaluation of relevant thermal and mechanical design criteria. The PhD thesis (CIFRE EDF) of G. Mangeon, was dedicated to the development of relevant RANS models for these industrial applications 103, 27. The collaboration with EDF is pursued within the ANR project MONACO_2025 and via the just started CIFRE PhD thesis of Corina Sanz Souhait.
 Moreover, the prediction of unsteady hydrodynamic loadings is a key point for operating and for safety studies of PWR power plants. Currently, the static loading is correctly predicted by RANS computations but when the flow is transient (as, for instance, in Reactor Coolant Pumps, due to rotor/stator interactions, or during operating transients) or in the presence of large, energetic, coherent structures in the external flow region, the RANS approach is not sufficient, whereas LES is still too costly for a wide use in the industry. This issue was the main focus of the PhD thesis (CIFRE EDF) of Vladimir Duffal, and is pursued within the ANR project MONACO_2025.
 For the design of high temperature solar receiver for concentrated solar power plants, flows are characterized by strong variations of the fluid properties, such that, even in the forced convection regime, they significantly deviate from isothermal flows, with a possible tendency to relaminarize, which can significantly reduce heat transfer. A better understanding and modeling of the physical mechanisms observed in turbulent flows with strong temperature gradients are important and was the focus of a recent collaboration with the LaTeP laboratory of UPPA.
 Thermal storage is interesting to decorrelate the production of heat or cold from its use whether for direct operation for a heat network (smoothing of heat supply to meet intermittent needs) or for power generation (phase shift between heat generation and power generation). The challenge is to study, via CFD, the dynamic and thermal behavior of the storage during the loading, resting and discharge phases. This is the focus of the PhD thesis of Alexis Ferré, cosupervised by R. Manceau and S. Serra (LaTeP).
4.3 Automotive propulsion
 The engine (underhood) compartment is a key component of vehicle design, in which the temperature is monitored to ensure the effectiveness and safety of the vehicle, and participates in 5 to 8% of the total drag and CO2 emissions. Dimensioning is an aerodynamic and aerothermal compromise, validated on a succession of road stages at constant speed and stopped phases (red lights, tolls, traffic jam). Although CFD is routinely used for forced convection, stateoftheart turbulence models are not able to reproduce flows dominated by natural convection during stopped phases, with a Rayleigh number of the order of ${10}^{10}$, such that the design still relies on costly, fullscale, wind tunnel experiments. This technical barrier must be lifted, since the ambition of the PSA group is to reach a full digital design of their vehicles in the 2025 horizon, i.e., to almost entirely rely on CFD. This issue was the focus of the PhD thesis (CIFRE PSA) of S. Jameel, supervised by R. Manceau, and also a part of the ANR project MONACO_2025 described in section 10.2.1, in the framework of which S. Jameel was hired as a postdoc until July 2021 and S.K. Jena from January 2022.
 The Power & Vehicles Division of IFPEN codevelops a CFD code, CONVERGE, to simulate the internal flow in sparkignition engines, in order to provide the automotive industry with tools to optimize their design. The RANS method, widely used in the industry, is not sufficiently reliable for quantitative predictions, and is only used as a tool to qualitatively compare different geometries. On the other hand, LES provides more detailed and accurate information, but at the price of a CPU cost unafordable for daily use in the industry. Therefore, IFPEN aims at developing the hybrid RANS/LES methodology, in order to combine the strengths of the two approaches. The PhD thesis of Hassan Afailal, cosupervised by Rémi Manceau, was focused on this issue. In the framework of the collaborative project ASTURIES (E2SUPPA/Inria/CEA/IFPEN), this collaboration with IFPEN will be pursued by the development of highorder methods in the CONVERGE code in order to make it possible to perform highly accurate and lowdissipative LES and hybrid RANS/LES in combustion engines.
4.4 Medical applications
Many medical applications exist where interactions between bubbles and biomaterials appear. CAGIRE is interested in a better understanding of the fundamental physics involved in such interactions, leading to improvements and innovation in current and future medical treatments with regard to their success rate, cost and safety:
 Lithotripsy is a noninvasive (the skin is not pierced) procedure used to treat kidney stones that are too large to pass through the urinary tract. Lithotripsy treats kidney stones by sending focused ultrasonic energy or shock waves directly to the stone first located with fluoroscopy (a type of Xray “movie”) or ultrasound (high frequency sound waves). The shock waves break a large stone into smaller stones that will pass through the urinary system. Lithotripsy allows persons with certain types of stones in the urinary system to avoid an invasive surgical procedure for stone removal. Lithotripsy involves cavitation bubbles as a primary or secondary mechanisms to attack the surface of the stone. Regarding success rates, for patients who are thought to be good candidates for this treatment, about 70 to 90 percent are found to be free of stones within three months of treatment. Furthermore, one should note that lithotripsy may include, but are not limited to, complications such as: bleeding around the kidney, infection, obstruction of the urinary tract by stone fragments, stone fragments left that may require more lithotripsies.
 Histotripsy is the first noninvasive, nonionizing, and nonthermal ablation technology guided by realtime imaging. Using focused ultrasound delivered from outside the body, histotripsy mechanically destroys tissue through cavitation, rendering the target into acellular debris. The material in the histotripsy ablation zone is absorbed by the body within 12 months, leaving a minimal remnant scar. Histotripsy has also been shown to stimulate an immune response and induce abscopal effects in animal models, which may have positive implications for future cancer treatment. Histotripsy has been investigated for a wide range of applications in preclinical studies, including the treatment of cancer, neurological diseases, and cardiovascular diseases. Phase I human trials have shown the initial safety and efficacy of histotripsy to treat patients with malignant liver tumors, BPH, and calcified aortic stenosis. Despite substantial technical, preclinical, and clinical progress to date, there is a large amount of future work necessary for technical development, preclinical research, and human studies before histotripsy can become a widespread clinical treatment modality.
 Drug delivery. Gasfilled microbubbles can be designed with drug and gasloaded interiors. A stabilizing coating surrounds the bubble which may be targeted to specific tissue by incorporating protein ligands on the surface. Drugs can be incorporated by themselves or, if insoluble in water, in an oil layer. Among the possible therapies, the most exciting is the possibility of the delivery of genetic material to a chosen site. Focused ultrasound is then used to cavitate the geneloaded microbubble and the shockwaves or microjets thus generated cause the genetic material to be injected into the surrounding cells. This technology can also be combined with endothelial cell barrier opening, which is performed prior the drug delivery. Indeed, the ultrasound irradiation of microbubbles produces jets which open the barrier for a few hours. This promotes the passage of large drug molecules necessary for specific treatments such as that of Alzheimer's disease.
5 Social and environmental responsibility
Impact of research results
The availability of improved RANS models and hybrid RANS/LES methods offering a better physical representativeness than models currently used in the industry, at a reasonable computational cost, will make it possible to improve the reliability of industrial numerical simulations, and thus to better optimize the systems, in order to reduce the environmental impact of transportation and industrial processes, and to improve the safety of installations and reduce the risks of accidental pollution.
Moreover, previous applications of hybrid RANS/LES methods have shown that it is possible to obtain an accuracy equivalent to LES with an energy consumption of the simulation reduced by a factor of about 200. This gain can be considerably increased in a complete industrial simulation with a much higher Reynolds number, leading to a drastic reduction of the environmental impact of the simulations themselves.
6 Highlights of the year
 Cagire organized the 17th ERCOFTAC SIG15 / MONACO_2025 workshop on turbulent natural convection flows, 1920 January 2023, Pau, France7. This event, coordinated by R. Manceau, brought together 25 people from different countries, and was both one of the periodic workshops of the SIG15 group of the ERCOFTAC European network, and the closing event of the MONACO_2025 ANR project.
 Discussions for a new collaboration with CEA Gramat were held during this year and the work will officially start during 2024. The collaboration will mainly consist of the funding of future PhD students. The first scientific subject to tackle concerns the numerical simulation of the attenuation of the effects of an explosion by an aqueous foam. Other subjects will follow such as the atomization of liquids resulting from the passage of a undeformable projectile at high speed through a barrel.
 A new collaboration with ETH Zürich and Storz Medical, a medical technology manufacturer, has started this year and concerns discovering the contribution of cavitation damage in kidney stone ablation. This work implies experiments using a medical extracorporeal shock wave lithotripter and Xrays visualizations that will take place at the European Synchrotron Radiation Facility in February 2024. These experiments will also allow us to better assess the quality of future stateoftheart simulations. The latter will constitute the first stones for following studies using exploratory technology for kidney stone ablation.
 A second collaboration has also started this year with ETH Zürich and concerns the use of both experiments and simulations to explore a new drugdelivery technique. It uses the interaction of a shock wave with an encapsulated droplet within a bubble. The droplet would contain the drug. The shock induces a strong collapse of the bubble which significantly enhances the atomization of the droplet. This also helps to choose the target location instead of disseminating the drug throughout the whole body's blood circulatory system.
 After a few years of suspended activity, the collaboration with SAFRAN Helicopter Engines was revived at the end of 2023 through the CIFRE thesis of Jules Mazaleyrat, also cosupervised by ONERA. This thesis is devoted to improving the EBRSM turbulence model, which we have been developing for many years, in the context of applications linked to cooling by jet impingement of turbine blades in helicopter engines.
 A new activity started this year in cooperation with Prof. S. Elaskar from the National University of Córdoba (Argentina). It is aimed at extending to reactive turbulent gaseous flows the temporal LES approach developed by the team for inert flows in a hybrid RANSLES context. During the twoweek visit of Prof. S. Elaskar, the problem of deriving a filtered chemical production term for the premixed turbulent combustion progress variable was addressed.
7 New software, platforms, open data
7.1 New software
7.1.1 AeroSol

Keywords:
High order finite elements, Parallel computing

Functional Description:
The AeroSol software is a high order finite element library written in C++. The code has been designed so as to allow for efficient computations, with continuous and discontinuous finite elements methods on hybrid and possibly curvilinear meshes. The work of the team CARDAMOM (previously Bacchus) is focused on continuous finite elements methods, while the team Cagire is focused on discontinuous Galerkin methods. However, everything is done for sharing the largest part of code we can. More precisely, classes concerning IO, finite elements, quadrature, geometry, time iteration, linear solver, models and interface with PaMPA are used by both of the teams. This modularity is achieved by mean of template abstraction for keeping good performances. The distribution of the unknowns is made with the software PaMPA , developed within the team TADAAM (and previously in Bacchus) and the team Castor.

News of the Year:
Highlights for the year 2023 concern:
 Functional tests: development of a python tool that will be included in the `ci`, based on `pytest`. Reference files, storing artifacts of the executions of the tests are generated, and the `ci` relaunch these tests and check the nonregression of the stored artifacts. Fix some feature in `ci` and parallel `ci` on Plafrim  Postprocessing tools were developed on the artifacts files for computing the order of convergence and for plotting the error.  Several bug fixes (geometrical partitioning, NetCDF)  Refactorization of the degrees of freedom handling. This should help the transition from PaMPA to DM2  Development of finite element basis and numerical schemes that preserve discretely curl or divergence with the discontinuous Galerkin method. This induced major changes because the degrees of freedom are no more accessed as [idof x nvar + ivar ] but in a transposed manner with a non regular pattern for the degrees of freedom. Implementation of initialization, error computation, a.s.o, and implementation of hyperbolic integrators with these new finite elements.  Development of covariant and contravariant geometrical transformations.  Some work was done on the macros using PaMPA for preparing the transition to DM2.  Induction model, two dimensional rotated waves model.  Computation of seminorm grad and div in the sense of distributions.
 URL:

Contact:
Vincent Perrier

Participants:
Mario Ricchiuto, Vincent Perrier, Heloise Beaugendre, Christopher Poette, Marco Lorini, Jonathan Jung, Anthony Bosco, Luca Cirrottola, Romaric Simo Tamou, Ibtissem Lannabi, Matthieu Haefele
7.1.2 DM2

Name:
Distributed Mesh and Data Manager

Keywords:
HPC, Data parallelism, High order finite elements, Unstructured meshes, Hybrid meshes

Functional Description:
DM2 is a C++ library for managing mesh and data on mesh in a MPI parallel environment. It is conceived to provide parallel mesh and data management in high order finite element solvers for continuum mechanics.
The user should provide a mesh file which is read by the library. Then DM2 is able to:
 Read the mesh, and read the data provided in the mesh file, possibly in parallel
 Redistribute the mesh in order to distribute the data on a given set of processors. This redistribution is made through a graph partitioner such as PARMETIS or PTSCOTCH.
 Allocate the memory in parallel if a number of unknown by entity type is provided by the user.
 Centralize the data.
 Compute the halo required for a numerical method. The halo is adapted for each of the possible discretization.
 Renumber mesh elements for making a difference between mesh elements that need or need not communication.
 Aggregate a mesh based on a metric for developing a multigrid method.

Release Contributions:
This version introduces overlap regions ("halos") among distributed mesh partitions. These halos are specialized for discontinuous or continuous schemes, but generic with respect to the (geometric) degree of the mesh cells. These halos allow to synchronize numerical data defined on a set of entities of the distributed mesh. Numerical data is again generic with respect to the degree of their polynomial approximation, the number and combinations of scalar/vector fields, and the size of the vector spaces.

News of the Year:
Contributions of this year are integrated in version v0.1. This version introduces overlap regions ("halos") among distributed mesh partitions. These halos are specialized for discontinuous or continuous schemes, but generic with respect to the (geometric) degree of the mesh cells. These halos allow to synchronize numerical data defined on a set of entities of the distributed mesh. Numerical data is again generic with respect to the degree of their polynomial approximation, the number and combinations of scalar/vector fields, and the size of the vector spaces. The continuous integration framework testes each commit on several 2D/3D hybrid meshes on which parallel mesh distribution and halos construction is performed, for each geometric and polynomial degree up to 4. Main classes are also covered by a set of unit tests.

Contact:
Vincent Perrier

Participants:
Vincent Perrier, Luca Cirrottola
7.1.3 UHAINA

Keywords:
Simulation, Ocean waves, Unstructured meshes, Finite element modelling

Scientific Description:
Operational platform for near shore coastal application based on the following main elements:
 Fullynonlinear wave propagation.
 Wave breaking handled by some mechanism allowing to mimic the energy dissipation in breakers.
 A high order finite element discretization combined with mesh and polynomial order adaptation for optimal efficiency.
 An efficient parallel object oriented implementation based on a hierarchical view of all the data management aspects cared for by middleware libraries developed at Inria within the finite element platform Aerosol.
 A modular wrapping allowing for application tailored processing of all input/output data (including mesh generation, and high order visualization).
 Spherical coordinates based on a local projection on a real 3D spherical map (as of 2021)
 Compilation with GUIX available (as of 2022)
 Homogenization and standardization of code outputs and hazard quatification (as of 2022)
 Correction of the management of dry/wet fronts in the presence of structures represented by a single high point (as of 2022)
 Use of FES for the calculation of the tide directly in UHAINA through an API. New compilation option for activation (as of 2022)
 Boundary conditions accounting tides from FES and corrected with the effect of the inverse barometer, for the simulation of the tidal propagation and the surge on domains at the regional scale (as of 2022)
 Hydraulic connections (e.g. sewers) in the simulation of urban flooding (as of 2022)
 Mass source term, for the injection of the volume of water overtopping structures not accounted in the elevation model during flooding episodes by sea surges (as of 2022)

Functional Description:
Waves simulation

Contact:
Mario Ricchiuto

Participants:
Mario Ricchiuto, Philippe Bonneton, David Lannes, Fabien Marche

Partners:
EPOC, IMAG, IMB
7.1.4 ECOGEN

Keyword:
Numerical simulations

Functional Description:
ECOGEN is a CFD platform dedicated to numerical simulation of compressible multiphase flows. It has the vocation to share academic research in the multiphase flow field with other academics but also with industrials and students.
Multimodels (single phase, multiphase with or without equilibrium). Multiphysics (thermal transfers, viscosity, surface tension, mass transfers). Multimeshes (Cartesian, unstructured, AMR). HPC.

News of the Year:
A new release, ECOGEN_v4.0, is available on GitHub. It includes new features and fixes bugs.
Major points:  Removed the version numbers of the input file names (break compatibility with previous version).  Possibility to use finite pressure relaxation on UEq model for more than two phases.  Possibility to initialize an unstructured simulation with the result of a previous simulation performed on a similar mesh and/or a different number of CPUs. This feature is particularly useful to fasten steady state convergence on a fine mesh using coarse mesh results.  PUEq phasechange model (handled through PTMu relaxation) does not require mass fraction threshold anymore to trigger mass transfer.  Add Moving Reference Frame coupling of a rotating region with a static one.  Renamed boundary condition names (break compatibility with previous version).  Immersed boundaries can be added in a Cartesian mesh domain (physicalEntity = 1).
Minor points:  Option to record boundary quantities such as pressure forces and shear stress (useful for aerodynamic coefficient computation).  Possibility to display cells' reference length on XML output with unstructured mesh.  Add a tutorial on mesh mapping and lowMach preconditionning options.  Add scripts related to droplet shockinduced cavitation.  Improve variable name style for Gnuplot output.  Increase code coverage by nonreg.  Updated AMR refinement criteria to match the different modelling.  Always a little more source code translation from French to English.  A wall is now considered as a symmetry BC if viscosity is ignored.  Update of documentation.
Fixes:  Fix the getTemperature() and copyPhase() methods for multiphase models.  Fix restart bug when using alphaNull on PUEq model.  Fix bug on simulation progress when using iteration control mode.  Fix a MPI data type that caused a crash during MPI_Allreduce on some compilers.  Minor fix for EulerKorteweg model.  Correction on UEq BC for volume fraction flux, using sM instead of uStar to respect transport equation.  Update nonregression scripts to make them compatible with OS X.  Correction for phase change with a secondorder method.
 URL:

Contact:
Kevin Schmidmayer

Participants:
Kevin Schmidmayer, Fabien Petitpas, Joris Cazé, Sébastien Le Martelot, Éric Daniel, Benedikt Dorschner, Solène Schropff, Adedotun AdeOnojobi, Fatima Gadiri

Partners:
CNES, ETHZ, California Institute of Technology
7.2 Open data
8 New results
8.1 Turbulence modelling
8.1.1 Improvement of the EBRSM RANS model
Participants: Rémi Manceau.
External collaborators: Gustave Sporschill (formerly CAGIRE, now Dassault), F. Billard (Dassault), M. Mallet (Dassault), A. Colombié (ONERA), F. Chedevergne (ONERA), E. Laroche (ONERA), S. Benhamadouche (EDF), J.F. Wald (EDF).
In order to accurately represent the complexity of the phenomena that govern the evolution of turbulent flows, an important part of our research focuses on the development of Reynoldsstress RANS models that take into account the wall/turbulence interaction by an original approach, elliptic blending 97, 101. Although this approach, has been successfully applied to various configurations (for instance 62), in order to take into account more subtle effects, during the theses of A. Colombié and G. Sporschill, in collaboration with ONERA and Dassault Aviation, respectively, we identified the importance of introducing a specific pressure diffusion model to correctly reproduce the dynamics of turbulence in impingement regions and in boundary layers subject to adverse pressure gradients, paving the way towards a wider application of the EBRSM in aeronautics 122, 72, 120, 121, 119. This activity is continued via the PhD thesis of J. Mazaleyrat in collaboration with SAFRAN HE and ONERA in the framework of turbine blade cooling by jet impingement.
8.1.2 Extension of RANS turbulence models to mixed and natural convection
Participants: Rémi Manceau, Puneeth Bikkanahally.
External collaborators: S.M. Saad Jameel (formerly Cagire, now Plastic Omnium), V. Herbert (PSAStellantis), F. Dehoux (formerly Cagire, now Framatome), S. Benhamadouche (EDF), S.K. Jena (formely Cagire, now TU Delft).
In the mixed and natural convection regimes, as presented in three invited lectures 98, 99, 20, the interaction mechanisms between dynamic and thermal fluctuations are complex and very anisotropic due to buoyancy effects, so that the natural turbulence modelling level to take them into account is secondmoment closure, i.e., Reynoldsstress models. When associating the EBRSM and the EBDFM, several modifications had to be introduced in natural convection for the scrambling term, the length scale of the elliptic blending, and especially by substituting a mixed time scale for the dynamic time scale in the buoyancy production term of the dissipation equation, which has a drastic positive impact on the predictions in the natural convection regime. This work, carried out in collaboration with EDF, leads to the first linear Reynoldsstress model able to accurately represent the wall/turbulence interaction in forced, mixed and natural convection regimes 76. However, some industrial partners, in particular PSA Group (now Stellantis), who encounter natural convection flows in the underhood compartment of vehicles, do not wish to use such sophisticated models, so we have developed an algebraic version of the Reynolds stress equation which thus constitutes an extension of the eddyviscosity models (buoyancyextended Boussinesq relation), within the framework of S. Jameel thesis 91, 90, 89, which can be easily implemented into any industrial and/or commercial CFD code. The application of such models to various configurations of differentiallyheated cavities showed that, depending on the situation, such buoyancy extensions can have an influence ranging from very significant to negligible 92.
8.1.3 HTLES: an original hybrid RANS/LES model
Participants: Rémi Manceau, Puneeth Bikkanahally, Mahitosh Mehta, Martin David.
External collaborators: Vladimir Duffal (formerly Cagire, now EDF), B. de Laage de Meux (EDF), H. Afailal (formerly CAGIRE, now IFPEN), Ch. Angelberger (IFPEN), A. Velghe (IFPEN).
Regarding hybrid RANS/LES, we have developed the HTLES (hybrid temporal LES) approach. The wall/turbulence interaction being fundamental for the applications of interest to EDF, V. Duffal's thesis 78 focused on the precise control of the transition from RANS to LES when moving away from the wall, through the improvement of the theoretical link between the turbulent scales and the form of the model equations, as well as the introduction of two different shielding functions to avoid the classical gridinduced separation and loglayer mismatch 80, 79, 18, i.e., the strong erroneous sensitivity of the results to the nearwall mesh. A significant result is that the study of wall pressure fluctuations and their spectra on periodic hills showed that the HTLES approach could reproduce these spectra as well as LES, down to a lower cutoff frequency than in LES due to the coarser mesh and the presence of the RANS zone 78, which suggests encouraging prospects for the prediction of mechanical and thermal fatigue. In the framework of the ANR project Monaco_2025, the thesis of P. Bikkanahally is devoted to the extension of the HTLES approach to natural convection. In differentially heated cavities, due to the coexistence of turbulent boundary layers and a laminar region in the centre, the shielding function introduced by V. Duffal causes a deterioration of the results. Good results are obtained by using instead a new shielding function based on the resolution of an elliptic relaxation equation 65, 17. Moreover, the thesis of H. Afailal, in collaboration with IFPEN, was dedicated to the development of the HTLES for the nonreactive internal aerodynamics of spark ignition engines. The aim was to adapt this approach to nonstationary, cyclic flows with moving walls, for which the main challenge was to provide a reliable evaluation of the mean turbulent energy, which is a crucial parameter for the control of the transition from RANS to LES, and is obtained by explicitly applying a differential temporal filter during the simulation to separate the timedependent mean and turbulent components of the flow 59.
8.1.4 Towards embedded LES
Participants: Rémi Manceau, Pascal Bruel, Puneeth Bikkanahally, Mahitosh Mehta, Martin David.
External collaborators: Fabien Dupuy (GDTech), Olivier Jegouzo (GDTech), Fabien Renard (GDTech).
In the framework of hybrid RANS/LES, a particularly attractive approach is Embedded LES, which consists in reserving the LES to a small area included in a global RANS domain, which is a particular strategy for using the zonal hybrid RANS/LES. However, the zonal approach is characterized by a predivision between RANS and LES zones and a discontinuous interface, which prohibits any evolution of the scale of description of turbulence during the calculation, which would allow an adaptability of the model according to physical criteria determined during the calculation. Our objective is therefore to develop embedded LES in the context of continuous approaches (CELES, Continuous Embedded LES), in which the interface between RANS and LES is now a diffuse interface. In these approaches, the domain is not split into subdomains, but the model evolves in a continuous manner so that it tends towards a RANS model or towards a LES model. The diffuse interface (grey area) is the transition area in which the model transitions from a RANS model to a LES model. It is then necessary, as in the zonal approach, to enrich the RANS solution by adding synthetic turbulence to avoid the drastic decrease of the total turbulent stress at the beginning of the LES zone which would strongly degrade the results. In the framework of the hybrid RANS/LES approach developed by Cagire, HTLES, this aspect consists in developing a volume enrichment approach based on a fluctuating force 106, 15. The development of such a CELES approach is the main purpose of the just started CELTIC project (postdoc of P. Bikkanahally), in collaboration with the SME GDTech. An adaptive determination of the RANS and LES regions based on physical criteria is the subject of the postdoc of M. David, in the framework of the Asturies project.
8.1.5 Turbulent premixed combustion in the flamelet regime: developing a closure model for the time filtered reaction rate
Participants: Pascal Bruel.
External collaborator: S. Elaskar (Universidad Nacional de Córdoba, Argentina).
The longterm objective pursued here is to extend the approach of temporal largeeddy simulation to turbulent reactive flows. As a first step towards this goal, the flamelet regime of isenthalpic turbulent premixed combustion was first considered. In such a regime, the combustion process can be represented through the evolution of a single progress variable whose time evolution resembles a bivalued telegraph signal. We first concentrate on the reaction rate, leaving aside for the moment the question of the closure of the filtered scalar flux. In a RANS approach, corresponding to an infinite time filter width, many models are available to close the mean reaction rate as a function of the mean progress variable. So the question raised now is: what happens to the relation between the filtered reaction rate and the filtered variable when the time filter width remains finite ? To guide our thinking, the development of the capacity of generating and filtering synthetic telegraph signals was deemed necessary. After considering in 22 the possibility of using the socalled "poor man NavierStokes" approach, we start developing a fortran code aimed at directly generating synthetic telegraph signals satisfying some a priori constraints so as to mimick real signals measured in such a combustion regime. With such a tool, we were able to recover the behavior of the filtered reaction rate for quasiinfinite time filter widths e.g. the RANS behavior. Our future activity will now concentrate on the numerical study of filtering the synthetic progress variable signal with finite time filter widths.
8.2 Highorder numerical methods and efficient algorithms
8.2.1 Efficient implementation of fluxreconstruction methods for combustion
Participants: Vincent Perrier.
External collaborators: Julien Bohbot, Julien Coatléven, Romaric SimoTamou, Quang Huy Tran.
In the framework of the PhD thesis of Romaric SimoTamou, fluxreconstruction methods were implemented, first in AeroSol for the NavierStokes system, and then in the Converge CFD code for high order computation of combustion and for benefiting of AMR in this code. For these schemes, new analyses of their dissipation and dispersion properties were performed and disseminated in 36.
8.2.2 Development of high order numerical schemes for axisymmetric turbulent flows
Participants: Anthony Bosco, Jonathan Jung, Vincent Perrier.
Part of the Asturies project aims at deriving high order numerical schemes for turbulent compressible flows in axisymmetric geometry. This year, the work was focused on the three following points:
 The derivation of conservative formulation for general advectiondiffusion conservation laws in axisymmetric coordinates. This led to a new high order discontinuous Galerkin method for axisymmetric coordinates, which is optimal order and in which the source term are unambiguously discretized and defined. This work was disseminated in 12 and in an extended version 37.
 The wall boundary conditions for a large family of turbulent models including the $k\epsilon $ models can be seen as a double boundary condition on one of the variables (for example homogeneous Neumann and homogeneous Dirichlet on $k$) and no boundary condition on $\epsilon $. A simplified version of this model with these boundary conditions can be seen as a mixed formulation for a biLaplacian equation, on which these types of boundary conditions are natural. Inspired by theses ideas, a new discontinuous Galerkin method was developed for this type of boundary condition on the simplified linear model, and was disseminated in 28.
8.3 Compressible and multiphase flows
8.3.1 LowMachnumber schemes
Participants: External collaborators: Jonathan Jung, Vincent Perrier, Ibtissem Lannabi, Esteban Coiffier, Thomas Galié.
Unfortunately, the only fix we found in our previous work that is accurate for high order acoustics computation is not Galilean invariant. The fix of 69 was extended from isentropic Euler system to full Euler system in 13.
Unfortunately, this fix is not Galilean invariant. This led us to try to tackle the problem in a different way from the numerical flux modification. We raised more fundamental questions on the connection between the low Mach number spurious mode responsible for a low accuracy and the long time behaviour of the wave system. In 14, we proved that on some finite domain configurations, the long time limit of the wave system exists, and that a numerical flux is low Mach number accurate if and only if its low Mach number acoustic development has a consistent long time behaviour. The spurious mode on the velocity at low Mach number can therefore be identified using the long time limit of the asymptotic acoustic system. Once this spurious mode is sharply identified, it can be filtered. This result is published in 93. Still based on this filtering method, a spurious mode was identified in the velocity obtained by the low Mach number fix which consists in centering the pressure gradient. This spurious mode may jeopardize the mesh convergence of the velocity 25. We also had the opportunity to disseminate our previous work on low Mach number flows at different conferences 29, 25, included invited ones 19.
8.3.2 Multiscale multiphase flows
Participants: Vincent Perrier, Kevin Schmidmayer.
As far as multiphase models are concerned, based on the ideas of 77, we have revisited the derivation of BaerandNunziato models 61. Usually, models are derived by averaging the Euler system; then the system of PDE on the mean values contains fluctuations which are modeled, often leading to relaxation terms and interfacial velocity and pressure which should also be modeled. This can be achieved by using physical arguments 116 or by ensuring mathematical properties 73. In 111, we have followed a slightly different path: we have supposed that the topology of the different phases follows an explicit model: the sign of a Gaussian process. Some parameters of the Gaussian process (mean, gradient of the mean) are linked with the averaged values of the flow (volume fraction), whereas others (autocorrelation function) are linked with the subscale structure of the flow. The obtained system is closed provided the parameters of the Gaussian process are known. Also, the system dissipates the phase entropies. Under some hypotheses that can be interpreted physically, asymptotic models can be derived in the interface flow limit or in the limit where the two fluids are strongly mixed. In these limits, different previously proposed models are recovered 116, 83, which does not necessarily ensure the same phase entropy dissipation properties. This work was disseminated this year in the conference 33.
8.3.3 Shockinduced cavitation within a droplet
Participants: Kevin Schmidmayer.
External collaborators: L. BiasioriPoulanges (ETH Zürich, Switzerland).
In 11 and 16, we investigated the shockinduced cavitation within a droplet which is highly challenged by the multiphase nature of the mechanisms involved. Within the context of heterogeneous nucleation, we introduced a thermodynamically wellposed multiphase numerical model accounting for phase compression and expansion, which relies on a finite pressurerelaxation rate formulation. We simulated (i) the spherical collapse of a bubble in a free field, (ii) the interaction of a cylindrical water droplet with a planar shock wave, and (iii) the highspeed impact of a gelatin droplet onto a solid surface. The determination of the finite pressurerelaxation rate was done by comparing the numerical results with the Keller–Miksis model, and the corresponding experiments of Sembian et al. and Field et al., respectively. For the latter two, the pressurerelaxation rate was found to be $\mu =3.5$ and $\mu =0.5$, respectively. Upon the validation of the determined pressurerelaxation rate, we ran parametric simulations to elucidate the critical Mach number from which cavitation is likely to occur. Complementing simulations with a geometrical acoustic model, we provided a phenomenological description of the shockinduced cavitation within a droplet, as well as a discussion on the bubblecloud growth effect on the droplet flow field. The usual prediction of the bubble cloud center, given in the literature, was eventually modified to account for the expansion wave magnitude.
8.3.4 Modelling of viscoelastic solids in multiphase flows
Participants: Kevin Schmidmayer.
External collaborators: N. Favrie (AixMarseille Université, France).
As a work in progress, an extension of the model of diffuse solid–fluid interfaces 109, 81 is proposed to deal with arbitrary complex materials such as porous materials in presence of plasticity and damage. These are taken into account through Maxwelltype models and are cast in the standard generalized materials. The specific energy of each solid is given in separable form: it is the sum of a hydrodynamic part of the energy depending only on the density and the entropy, an elastic part of the energy which is unaffected by the volume change, and a compaction part taking into account the compaction effects. It allows us to naturally pass to the fluid description in the limit of vanishing shear modulus. In spite of a large number of governing equations, the model has a simple mathematical structure. The model is well posed both mathematically and thermodynamically, i.e. it is hyperbolic and compatible with both laws of thermodynamics. The resulting model can be applied in situations involving an arbitrary number of fluids and solids. In particular, we are showing the ability of the model to describe complex plasticity (Gurson 86) and damage (Mazars 105) models.
8.4 Analysis and simulation of turbulent flows and heat transfer
8.4.1 Effusion cooling
Participants: Rémi Manceau, Pascal Bruel.
External collaborators: Ph. Reulet (ONERA), E. Laroche (ONERA), D. Donjat (ONERA), F. Mastrippolito (formerly CAGIRE, now SAFRAN HE).
As regards wall cooling by effusion (multiple jets in crossflow), our MAVERIC experimental facility does not allow us to carry out thermal measurements, so we approached ONERA Toulouse to collaborate on the effects of gyration (angle of the jets with respect to the incident flow) on the heat transfer between the fluid and the wall, within the framework of the European project SOPRANO. We then took up the challenge of carrying out RANS simulations with the EBRSM model on a configuration of unprecedented complexity for us, consisting of 10 rows of 9 holes, in 90degree gyration, representative of effusion cooling problems in aeronautical combustion chambers. Comparisons between calculations and experiments have shown the relevance of using the EBRSM model and the importance of taking into account conjugate heat transfer 113, 104. In the framework of the Asturies project, the case, the database of a jet in crossflow measured in the MAVERIC facility is currently under investigation with the adaptive strategy developed by M. David, in order to serve as a demonstrator of this agile simulation method.
8.4.2 Thermocline energy storage
Participants: Rémi Manceau, Alexis Ferré.
External collaborators: S. Serra (LaTEP, UPPA), J. Pouvreau (CEA), A. Bruch (CEA).
A collaboration started at the end of 2020 with the CEA LITEN in Grenoble and the LaTEP of UPPA on thermocline energy storage. An experimental facility is being developed at the CEA and RANS simulations are underway to understand the dynamics of this type of flows, to determine the influence of the turbulence generated by the filling of the tank on the quality of the thermocline, in order to optimize the system and provide data to support the development of 1D models used in the optimization of heat networks. A particular attention has been paid to the approximation used for variations of density with temperature. Due to the wide range of temperatures, it was shown that the standard Boussinesq approximation is not valid but a quadratic Boussinesq approximation was proposed, which gives results very close to the more complex lowMach number approximation, with a computational cost reduced by a factor of two and an improved numerical stability 82, 23.
9 Bilateral contracts and grants with industry
Participants: Rémi Manceau, Vincent Perrier, Jonathan Jung, Pascal Bruel, Anthony Bosco, Mahitosh Mehta, Martin David, Romaric Simo Tamou, Alexis Ferré, Esteban Coiffier.
9.1 Bilateral contracts with industry
 CEA: “Agile simulation of turbulent internal flows”, contract in the framework of the Asturies project.
 CEA: “Collaboration contract for the PhD thesis of A. Ferré".
 CEA: “Collaboration contract for the PhD thesis of E. Coiffier".
 IFPEN: “Collaboration contract for the PhD thesis of Romaric SimoTamou".
9.2 Bilateral grants with industry
 CEA: “CFD and experimental study of a thermoclinetype thermal storage for an optimized design and data entry of component scale models in the framework of a multiscale approach”, PhD student Alexis Ferré.
 CEA: “Development of Fast, Robust and Accurate numerical methods for turbulence models on Complex Meshes” (1/2 Grant), PhD student Anthony Bosco.
 CEA: “Analyse et simulation numériques de discrétisations décalées en thermohydraulique diphasique”, PhD student Esteban Coiffier.
 IFPEN: "Développement de schémas d'ordre élevé pour un solveur cartésien / AMR pour la modélisation LES de la combustion.", PhD student Romaric SimoTamou.
10 Partnerships and cooperations
10.1 International research visitors
10.1.1 Visits of international scientists
Other international visits to the team
Sergio Elaskar

Status:
Professor.

Institution of origin:
National University of Córdoba.

Country:
Argentina.

Dates:
November 6 to November 18.

Context of the visit:
Followup of the A17A07 Ecos Sud project.

Mobility program/type of mobility:
CNRS funded research stay.
10.2 National initiatives
10.2.1 ANR MONACO_2025
Participants: Rémi Manceau, Puneeth Bikkanahally.
This project started in 2018 and ended in 2023. The ambition of the MONACO_2025 project, coordinated by Rémi Manceau, was to join the efforts made in two different industrial sectors in order to tackle the industrial simulation of transient, turbulent flows affected by buoyancy effects. It brings together two academic partners, the projectteam Cagire hosted by the university of Pau, and the institute Pprime of the CNRS/ENSMA/university of Poitiers (PPRIME), and R&D departments of two industrial partners, the PSA group and the EDF group, who are major players of the automobile and energy production sectors, respectively.
 The main scientific objective of the project is to make a breakthrough in the unresolved issue of the modelling of turbulence/buoyancy interactions in transient situations, within the continuous hybrid RANS/LES paradigm, which consists in preserving a computational cost compatible with industrial needs by relying on statistical approaches where a finegrained description of the turbulent dynamics is not necessary. The transient cavity flow experiments acquired during MONACO_2025 will provide the partners and the scientific community with an unrivalled source of knowledge of the physical mechanisms that must be accounted for in turbulence models.
 The main industrial objective is to make available computational methodologies to address dimensioning, reliability and security issues in buoyancyaffected transient flows. It is to be emphasized that such problems are not tackled using CFD at present in the industry. At the end of MONACO_2025, a panel of methodologies, ranging from simple URANS to sophisticated hybrid models based on improved RANS models, was evaluated in transient situations, against the dedicated cavity flow experiments and a real car underhood configuration. This final benchmark exercise will form a decisionmaking tool for the industrial partners, and will thus pave the way towards highperformance design of lowemission vehicles and highly secure power plants. In particular, the project is in line with the Full Digital 2025 ambition, e.g., the declared ambition of the PSA group to migrate, within the next decade, to a design cycle of new vehicles nearly entirely based on CAE (computer aided engineering), without recourse to expensive fullscale experiments.
10.2.2 ANR LAGOON
Participants: Vincent Perrier.
The ANR project Lagoon was funded by ANR in 2021 within the section CE46  Modèles numériques, simulation, applications.
Coastal areas host around 10% of the world's population and a huge amount of economic activities. Climate change is expected to increase coastal flooding hazard in years to come. In this project, we propose to develop a numerical tool for the stormsurges predictions.
For four years, a joint effort between the partners of this project among others has been done for the development of a numerical tool able to tackle planetary computations with high resolution at the coast: the Uhaina code, based on top of the AeroSol library. The scope of this project is to increase the computational performance of our modelling platform, in order to upgrade it as an efficient and accurate tool for stormsurge predictions in different future climate scenarios. To achieve this goal and producing results which go beyond the stateoftheart, our efforts will be focused on the following numerical and informatics developments, devoted to decrease the run time of the model in operational conditions:
 Development of lowFroude accurate ImplicitExplicit (ImEx) time integration strategy.
 Development of scalable aggregationbased multigrid methods for addressing the efficiency of the inversion of the (non)linear systems induced by implicit time stepping. For the data generation, two stages IO, insitu and intransit data postprocessing are strategies that will be evaluated with existing technologies and will be implemented to improve the performance of the production code.
 The numerical tool will be validated on 19792014 sea level reanalysis, and be used for the generation of a database of sea level projections on future climate CMIP6 projections.
The code developed within this project will be freely distributed, with a strong effort put on reproducibility of results. Data generated for both the sea level reanalysis and the database of sea level projection for future climate projections will be distributed towards the community.
10.2.3 ASTURIES
Participants: Rémi Manceau, Vincent Perrier, Jonathan Jung, Pascal Bruel, Anthony Bosco, Mahitosh Mehta, Romaric Simo Tamou, Martin David.
Call: ISite E2S UPPA "Exploring new topics and facing new scientific challenges for Energy and Environment Solutions"
Dates: 20202024
Partners: CEA CESTA ; IFPEN
In the context of internal turbulent flows, relevant to aeronautic and the automotive propulsion and energy production sectors, ASTURIES aims at developing an innovative CFD methodology. The next generation of industrial CFD tools will be based on the only approach compatible with admissible CPU costs in a foreseeable future, hybrid RANS/LES. However, stateoftheart hybrid RANS/LES methods suffer from a severe limitation: their results are strongly userdependant, since the local level of description of the turbulent flow is determined by the mesh designed by the user.
In order to lift this technological barrier, an agile methodology will be developed: the scale of description of turbulence will be locally and automatically adapted during the computation based on local physical criteria independent of the grid step, and the mesh will be automatically refined in accordance. Such an innovative approach requires the use of advanced nearwall turbulence closures, as well as highorder numerical methods for complex geometries, since lowdissipative discretization is necessary in LES regions. Morevover, the identification of relevant physical RANStoLES switchover criteria and the refined validation of the method will strongly benefit from dedicated experiments.
The objectives of the project thus consist in:
 Proposing a robust and efficient implementation of elliptic relaxation/blending turbulence models in the context of highorder Discontinuous Galerkine methods.
 Develop local physical criteria in order to get rid of the (explicit or implicit) dependence on the grid step of the transition from RANS to LES.
 Develop an automatic remeshing strategy which ensures consistency with the selfadaptation of the model.
 Validate the global methodology based on the 3 preceding points for configurations representative of industrial internal turbulent flows.
The development of such a methodology, based on hybrid RANS/LES modelling, with lowdissipative and robust numerical methods, independant of the initial design of a grid by the user, compatible with unstructured meshes for complex industrial geometries, in the context of HPC, is thus the ambitious, but reachable, objective of the project.
10.3 Regional initiatives
10.3.1 CELTIC
Participants: Rémi Manceau, Pascal Bruel, Puneeth Bikkanahally.
CELTIC (Continuous Embedded LES for Turbulent flows in Industrial Configurations) is a projet accepted in the call ESR 2022 of the NewAquitaine Region, in partnership with the local SME GDTech.
The project aims at proposing a new model of the forcing term allowing enrichment at the diffuse interfaces between RANS and LES in continuous hybrid RANS/LES models for the simulation of turbulent flows. This will make possible the development of an innovative simulation methodology, continuous embedded LES (CELES), which consists in restricting the finegrained model (LES) to regions where it is necessary, surrounded by the rest of the domain using a statistical approach (RANS). The combination of the fact that CELES will be based on hybrid RANS/Continuous LES approaches, easy to use in industrial applications, and on a seeding by volume forcing applicable in all situations will make it a particularly attractive method for the industry, which will bring to our industrial partner GDTech and its regional customers (for example SAFRAN HE) a real value compared to the numerical simulation methods available today.
11 Dissemination
Participants: Rémi Manceau, Jonathan Jung, Vincent Perrier, Kevin Schmidmayer, Pascal Bruel, Martin David, Mahitosh Mehta, Ibtissem Lannabi, Anthony Bosco, Puneeth Bikkanahally Muni Reddy.
11.1 Promoting scientific activities
11.1.1 Scientific events: organisation
General chair, scientific chair
 R. Manceau organized the 17th ERCOFTAC SIG15 / MONACO_2025 workshop8. This workshop, organized under the auspices of the SIG15 of the european ERCOFTAC network, which is also the final workshop of the MONACO_2025 project, was held in Pau 1920 January 2023.
Member of the organizing committees
 Member of the scientific committee of the International Symposium on Turbulence, Heat and Mass Transfer since 2006 [R. Manceau]
11.1.2 Journals
Member of the editorial boards
 Advisory Board of International Journal of Heat and Fluid Flow [R. Manceau]
 Advisory Board of Flow, Turbulence and Combustion [R. Manceau]
Reviewer  reviewing activities
 Aerosp. Sci. Technol. [P. Bruel]
 Communications in Computational Physics (1) [V. Perrier]
 Computers and Fluids (3) [R. Manceau (2), J. Jung (1)]
 Computers and Mathematics with Applications 1) [ V. Perrier]
 ESAIM Proceedings (1) [V. Perrier]
 Flow, Turbulence and Combustion (2) [R. Manceau]
 Int.J. Heat and Fluid Flow [R. Manceau]
 Int.J. Heat and Mass Transfer [P. Bruel]
 Int.J. Thermofluids (2) [R. Manceau]
 J. Computational Physics (4) [R. Manceau, V. Perrier (2), K. Schmidmayer]
 J. Fluid Mechanics (2) [R. Manceau, K. Schmidmayer]
 Physics of Fluids (2) [R. Manceau, K. Schmidmayer]
 Proceedings of the Royal Society A [K. Schmidmayer]
 Proceedings of FVCA10 conference [J. Jung]
11.1.3 Invited talks
11.1.4 Leadership within the scientific community
 R. Manceau has been a member of the Standing committee of the Special Interest Group Turbulence modelling (SIG15) of ERCOFTAC since 2005, together with 9 other committee members (S. Jakirlić [chairman], F. Menter, S. Wallin, D. von Terzi , B. Launder, K. Hanjalić, W. Rodi, M. Leschziner, D. Laurence). The main activities of the group is to organize international workshops and thematic sessions in international congresses.
 Vincent Perrier coordinates the ANR Project LAGOON, a 4year project started in 2022. The partners are: the CARDAMOM projectteam of Inria Bordeaux and the BRGM.
 Rémi Manceau coordinated the ANR Project MONACO_2025, a 4year project started in 2018 and ended in 2023. The partners were: the institute PPrime, PSA Group and EDF.
 Rémi Manceau coordinates the 4year E2SUPPA project ASTURIES, which involves CEA and IFPEN.
11.1.5 Research administration
 Member of the LMAP council [Rémi Manceau].
 Member of the CDT, in charge of the evaluation of software projects at the Inria Bordeaux center [Vincent Perrier].
 Elected member of the Inria evaluation committee and member of the board [Vincent Perrier], Until August 2023. 9. The report of our last four years is available in 38
 Member of the CT3Num committee of Pau University, in charge of managing the computing resources and projects at Pau University [Vincent Perrier].
 Member of the comité des utilisateurs des moyens de calcul at INRIA [Vincent Perrier]
 Member of the scienfic board of INRIA (Since December 2023) [Vincent Perrier]
11.2 Teaching  Supervision  Juries
11.2.1 Teaching
(Legend: L1L2L3 corresponds to the 3 years of undergraduate studies, leading to the BSc degree; M1M2 to the 2 years of graduate studies, leading to the MSc degree; E1E2E3 to the 3 years of engineering school, equivalent to L3M1M2, leading to the engineer/MSc degree)
 L1 [J. Jung]: Research and innovation (lectures: 1.5h/year), Université de Pau et des Pays de l'Adour, Pau, France.
 L1 [J. Jung]: Mathematical Algorithms 1 and Python (lectures: 9h/year) Mathematics, University of Pau (UPPA).
 L2 [J. Jung]: Numerical analysis for vectorial problems (lectures: 10.5h/year), Mathematics, Université de Pau et des Pays de l'Adour, Pau, France.
 L2 [J. Jung]: Scientific computing (labs: 58.5h/year), Informatics, University of Pau (UPPA).
 M1 [J. Jung]: Tools for scientific computing (lectures: 9.75/year, labs: 9h75/year), MMS, Université de Pau et des Pays de l'Adour, Pau, France.
 M2 [R. Manceau]: Turbulence modelling (in English), 27h30/year, International Master program Turbulence, ISAEENSMA/École centrale de Lille, France.
 E3 [R. Manceau]: Industrial codes for CFD (in English), 12h30/year, ISAEENSMA, Poitiers, France 54.
 E3 [R. Manceau]: Advanced physics–Turbulence modelling for CFD, 16h/year, ENSGTI, France 56.
 E2 [K. Schmidmayer]: Coupled heat transfer, 20h/year, ENSGTI, Pau, France.
 E2 [K. Schmidmayer]: Convective transfer of heat and matter, 16h/year, ENSGTI, Pau, France.
 M1 [K. Schmidmayer]: Introduction to Python, 16h/year, Master MSID, Pau, France.
 L2 [K. Schmidmayer]: DocumentaryCommunication Project, 4h/year, Master CMI, Pau, France.
 E3 (M. David): Advanced physics (classes: 6h/year, labs: 5h/year) ENSGTI
 E3 (M. David): Modelling and simulation in fluid mechanics (lectures: 4h/year; classes: 16h/year). ENSGTI.
 M2 (M. David): Modelling of energy systems CFD for industry using fluent (lectures: 10.5h/year; classes: 30h/year). UPPA, Master SIMOS.
 L1 (I. Lannabi): Descriptive statistics (22.5h/year, labs), Mathematics & MIASHS. University of Pau (UPPA).
 L1 (I. Lannabi) Mathematical Algorithms 1 and Python (49.5h/year, labs) Mathematics, University of Pau (UPPA).
 L2 (A. Bosco) Scientific computing (18h/year labs), computer science, UPPA.
 L1 MIASHS/L2 Natural sciences (A. Bosco) Descriptive statistics (22.5h/year labs), UPPA.
11.2.2 Supervision
 PhD (defended Dec. 2023): Puneeth Bikkanahally Muni Reddy, “Modelling turbulent flows in natural convection regimes using hybrid RANSLES approaches”, UPPA, ANR project Monaco_2025, Rémi Manceau.
 PhD (defended Nov. 2023): Mahitosh Mehta, “Development of an agile methodology for hybrid RANSLES computations of turbulent flows”, UPPA, E2SUPPA Asturies project, Rémi Manceau
 PhD in progress: Romaric Simo Tamou, “Development of highorder methods in a Cartesian AMR/Cutcell code. Application to LES modelling of combustion”, IFPEN, E2SUPPA Asturies project, Vincent Perrier.
 PhD in progress: Anthony Bosco, “Development of Fast, Robust and Accurate numerical methods for turbulence models on Complex Meshes” CEA/E2SUPPA, E2SUPPA Asturies project, Vincent Perrier and Jonathan Jung.
 PhD in progress: Alexis Ferré, “CFD and experimental study of a thermoclinetype thermal storage for an optimized design and data entry of component scale models in the framework of a multiscale approach”, CEA LITEN, Rémi Manceau.
 PhD in progress: Ibtissem Lannabi , “Discontinuous Galerkin methods for low Mach flows in fluid mechanics”, EDENE project (H2020 MarieSklodowskaCurie COFUND), Jonathan Jung and Vincent Perrier.
 PhD in progress: Esteban Coiffier, "Analyse et simulation numériques de discrétisations décalées en thermohydraulique diphasique", CEASaclay, Vincent Perrier & Jonathan Jung.
 PhD in progress: Jules Mazaleyrat, "Modélisation numérique d'une turbine refroidie par impact de jets : dérivation de modèles RANS adaptés sur la base d'une approche LES”, SAFRAN HE and ONERA, Rémi Manceau.
 PhD in progress: Corina Sanz Souhait, “Industrialisation des modèles RANS avancés avec transferts thermiques pour la convection forcée, mixte et naturelle”, EDF, Rémi Manceau.
11.2.3 Juries
 Reviewer of the PhD thesis of S. Meynet, Normandy university [R. Manceau]
 Reviewer of the PhD thesis of F. Uncu, Sorbonne university [R. Manceau]
 Reviewer of the PhD thesis of M. Djeddou, university of Lorraine [R. Manceau]
 Reviewer of the PhD thesis of P. Seize, Supaero [V. Perrier]
 Reviewer of the PhD thesis of M. Petrella, ETH Zürich [V. Perrier]
 Reviewer of the PhD thesis of J. Bussac, Nantes [V. Perrier]
 Reviewer of the PhD thesis of G. Jomée, Marseille [V. Perrier]
 Member of the jury of the PhD thesis of M. Stuck, university of Toulouse [R. Manceau]
 Member of the jury of the PhD thesis of M. Mehta, university of Pau [R. Manceau]
 Member of the jury of the PhD thesis of P. Bikkanahally, university of Pau [R. Manceau]
 Member of the jury of the PhD thesis of P. Allegrini, University of Toulouse [V. Perrier]
11.3 Popularization
11.3.1 Education
 P. Bruel supervized a oneweek stay of observation of J.B. Laurouaa, middle school student from Collège D. Argote (Orthez).
11.3.2 Interventions

48schmidmayer:hal04209499

49schmidmayer:hal04245972

51schmidmayer:hal04325167

52schmidmayer:hal04337844

47schmidmayer:hal03960412

50schmidmayer:hal04225207
 P. Bruel participated in the «Carrefour des Métiers» organized by "La ZAP des Gaves (Académie de Bordeaux)" on March 30, 2023. He manned a booth during the all day with the objective of explaining the activity of a researcher to a large audience of middle school students.
12 Scientific production
12.1 Major publications
 1 articleA phenomenological analysis of droplet shockinduced cavitation using a multiphase modelling approach.Physics of Fluids35January 2023, 013312HALDOI
 2 articleA low Mach correction able to deal with low Mach acoustics.Journal of Computational Physics3782019, 723759HAL
 3 articleConstruction of modified Godunov type schemes accurate at any Mach number for the compressible Euler system.Mathematical Models and Methods in Applied SciencesNovember 2016HALDOI
 4 articleDevelopment and Validation of a new formulation of Hybrid Temporal Large Eddy Simulation.Flow, Turbulence and Combustion2021HALDOI
 5 articleLES fluidsolid coupled calculations for the assessment of heat transfer coefficient correlations over multiperforated walls.Aerospace Science and Technology532016, 13HALDOI
 6 articleRungeKutta discontinuous Galerkin method for the approximation of Baer and Nunziato type multiphase models.Journal of Computational Physics23111February 2012, 40964141HALDOI
 7 articleAn interface condition to compute compressible flows in variable cross section ducts.Comptes Rendus MathématiquesFebruary 2016HALDOI
 8 articleRecent progress in the development of the Elliptic Blending Reynoldsstress model.International Journal of Heat and Fluid Flow2015, 32HALDOI
 9 articleExtension to various thermal boundary conditions of the elliptic blending model for the turbulent heat flux and the temperature variance.Journal of Fluid Mechanics905A1December 2020, 134HALDOI
 10 articleGodunovtype schemes with an inertia term for unsteady full Mach number range flow calculations.Journal of Computational Physics281January 2015, 35HALDOI
12.2 Publications of the year
International journals
 11 articleA phenomenological analysis of droplet shockinduced cavitation using a multiphase modelling approach.Physics of Fluids35January 2023, 013312HALDOIback to text
 12 articleDiscontinuous Galerkin methods for axisymmetric flows.Computers and Fluids270February 2024, 106139HALDOIback to text
 13 articleExtension of an allMach Roe scheme able to deal with low Mach acoustics to full Euler system.ESAIM: Proceedings and SurveysJuly 2023HALback to text
 14 articleLong time behavior of finite volume discretization of symmetrizable linear hyperbolic systems.IMA Journal of Numerical Analysis431January 2023, 326356HALDOIback to text
 15 articleAn active hybrid ReynoldsAveraged NavierStokes/Large Eddy Simulation approach for grey area mitigation.Physics of Fluids352023HALDOIback to textback to text
 16 articleGeometry effects on the droplet shockinduced cavitation.Physics of Fluids356June 2023, 063315HALDOIback to text
Invited conferences
 17 inproceedingsModelling turbulent flows in the natural convection regime using hybrid RANSLES approaches.17th ERCOFTAC SIG15/MONACO2025 workshop: Turbulent natural convection flows in differentially heated cavitiesPau, FranceJanuary 2023HALback to textback to text
 18 inproceedingsDevelopment and Validation of a new formulation of Hybrid Temporal LargeEddy Simulation.17th ERCOFTAC SIG15/MONACO2025 workshop: Turbulent natural convection flows in differentially heated cavitiesPau, FranceJanuary 2023HALback to textback to text
 19 inproceedingsOn low Mach number fixes for Roetype schemes.CEASMAI/GAMNI  35ème Séminaire sur la mécanique des fluides numériqueParis, FranceJanuary 2023HALback to textback to text
 20 inproceedingsModélisation de la turbulence en convection naturelle (conférence introductive).Journées thématiques de la SFT. Convection naturelle : aspects fondamentaux et applicationsOrsay, FranceJuly 2023HALback to textback to text
International peerreviewed conferences
 21 inproceedingsTowards selfadaptivity in hybrid RANS/LES based on physical criteria.THMT 2023  10th International Symposium on Turbulence, Heat and Mass TransferRome, ItalySeptember 2023HALback to text
 22 inproceedingsEcuaciones de NavierStokes de hombre pobre applicadas a llamas premezcladas.Matemática Aplicada, Computacional e Industrial (MACI, ISSN: 23143282)MACI 2023  IX Congreso de Matemática Aplicada, Computacional e Industrial9Santa Fe, ArgentinaMay 2023HALback to text
 23 inproceedingsCFD study of thermocline formation in stratified water storage: Consideration of a secondorder Boussinesq approximation to model buoyancy effects and its application to assess the impact of operating conditions.IHTC17  ID: 435Proceedings of the 17th International Heat Transfer Conference, IHTC17 14 – 18 August 2023, Cape Town, South AfricaCape Town, South AfricaAugust 2023HALback to text
 24 inproceedingsAnalysis of the Reynolds stress tensor for unsteady flows in URANS models.Matemática Aplicada, Computacional e Industrial (MACI, ISSN: 23143282)MACI 2023  IX Congreso de Matemática Aplicada, Computacional e Industrial9 (à paraitre, to appear)Santa Fe, ArgentinaMay 2023HAL
 25 inproceedingsOn the convergence of Godunov scheme with a centered discretization of the pressure gradient.FVCA X 2023  Finite Volumes for Complex Applications XStrasbourg, FranceOctober 2023HALback to textback to text
 26 inproceedingsGrey area mitigation in hybrid RANS/LES by means of volume forcing.Proc. 10th Int. Symp. Turbulence, Heat and Mass TransferTHMT 2023  10th International Symposium on Turbulence, Heat and Mass TransferRome, ItalySeptember 2023HAL
 27 inproceedingsConjugate heat transfer with different fluidsolid physical properties: a differential flux model based on elliptic blending.THMT 2023  10th International Symposium on Turbulence, Heat and Mass TransferRome, ItalySeptember 2023HALback to text
Conferences without proceedings
 28 inproceedingsVariational Formulation of Wall Boundary Conditions of RANS Models in a Discontinuous Galerkin Framework.CFC 2023  22nd Computational Fluids ConferenceCannes, FranceApril 2023HALback to text
 29 inproceedingsLink between the low Mach number accuracy problem and the solution of a wave system.NUMHYP 2023  Numerical Methods for Hyperbolic ProblemsBordeaux, FranceJune 2023HALback to text
 30 inproceedingsComparison of turbulence models for the case of a differentially heated square cavity.17th ERCOFTAC SIG15/MONACO2025 workshop: Turbulent natural convection flows in differentially heated cavitiesPau, FranceJanuary 2023HAL
 31 inproceedingsCubic cavity with centrally placed partially heated inner obstacle: evaluation of the turbulence models.17th ERCOFTAC SIG15/MONACO2025 workshop: Turbulent natural convection flows in differentially heated cavitiesPau, FranceJanuary 2023HAL
 32 inproceedingsMONACO_2025: Modelling natural convection: A Challenge for the Full Digital 2025 Ambition.17th ERCOFTAC SIG15/MONACO_2025 workshop: Turbulent natural convection flows in differentially heated cavitiesPau, FranceJanuary 2023HAL
 33 inproceedingsDerivation of fully closed twophase models of BaerandNunziato type.The 11th International Conference on Multiphase FlowKobe, JapanApril 2023HALback to text
 34 inproceedingsOn bubble cloud growth in shockdroplet interaction.ICMF 2023  11th International Conference on Multiphase FlowKobe, JapanApril 2023HAL
 35 inproceedingsDroplet shockinduced cavitation using a multiphase modelling approach.LMAP seminarPau, FranceJanuary 2023HAL
 36 inproceedingsHigh order Flux Reconstruction schemes for turbulent flows and spectral analysis.10th International Congress on Industrial and Applied Mathematics (ICIAM 2023)Tokyo, JapanAugust 2023HALback to text
Reports & preprints
 37 reportDiscontinuous Galerkin methods for axisymmetric flows: extended version.RR9524INRIAOctober 2023, 49HALback to text
 38 reportBilan de la mandature 20192023 de la Commission d'Évaluation Inria.InriaAugust 2023HALback to text
 39 miscA selfadaptive strategy for hybrid RANS/LES based on physical criteria.January 2024HAL
Other scientific publications
 40 inproceedingsOn a discontinuity capturing Finite Volume method that can solve fully incompressible flows.SMAI 2023  Congrès de la Société des Mathématiques Appliquées et IndustriellesLe Gosier, Guadeloupe, FranceMay 2023HAL
 41 inproceedingsOn a discontinuity capturing Finite Volume method that can solve fully incompressible flows.Groupe de Travail Mathématiques pour le Nucléaire (GdR MaNu) 2023Le Croisic, FranceOctober 2023HAL
12.3 Other
Scientific popularization
 42 miscCampus des enfants.July 2023HAL
 43 miscFête de la science  village des sciences.October 2023HAL
 44 miscMaths en jeans.March 2023HAL
 45 miscJournée Filles, maths et informatique.December 2023HAL
 46 inproceedingsBehavior of the compressible Euler equations in the low Mach number limit.Journées Doctorales de la Fédération MARGAUx 2023Poitiers (Université de Poitiers), FranceMay 2023HAL
 47 inproceedingsUne introduction aux systèmes chaotiques et bulles de cavitation.Mathematicum Séminaire de Mathématiques et leurs ApplicationsPau, FranceJanuary 2023HALback to text
 48 inproceedingsL'accumulation de données, la face cachée de l'intelligence artificielle, vu par Albert Kahn avec sa documentation du monde en 1920.Journées Européennes du patrimoine 2023Pau (FRA), FranceSeptember 2023HALback to text
 49 inproceedingsLe double pendule, une représentation du chaos.Villages des SciencesPau, FranceOctober 2023HALback to text
 50 inproceedingsNos futurs : Jumeaux numériques et modèles de langages.Nuit Européenne des chercheursPau, FranceSeptember 2023HALback to text
 51 inproceedingsModélisation de la mécanique des fluides.1 scientifique, 1 classe : Chiche ! Lycée Saint John PersePau, FranceDecember 2023HALback to text
 52 inproceedingsModélisation de la mécanique des fluides.1 scientifique, 1 classe : Chiche ! Lycée Saint John PersePau, FranceDecember 2023HALback to text
Educational activities
 53 unpublishedCodes de calcul industriels pour la simulation des écoulements turbulents.February 2024, MasterFranceHAL
 54 unpublishedIndustrial codes for CFD.February 2024, MasterFranceHALback to text
 55 unpublishedModelisation de la turbulence pour la CFD.October 2023, MasterFranceHAL
 56 unpublishedTurbulence modelling for CFD.October 2023, MasterFranceHALback to text
12.4 Cited publications
 57 inproceedingsA RANS assisted LES approach.Direct and LargeEddy Simulation XI25ERCOFTAC SeriesSpringer, Cham2019, 159165back to text
 58 articleDevelopment and validation of a hybrid temporal LES model in the perspective of applications to internal combustion engines.Oil & Gas Science and Technology  Revue d'IFP Energies nouvelles742019, 56HALDOIback to text
 59 phdthesisNumerical simulation of nonreactive aerodynamics in Internal Combustion Engines using a hybrid RANS/LES approach.Université de Pau et des Pays de l'AdourDecember 2020HALback to text
 60 articleEvaluation of numerical wall functions on the axisymmetric impinging jet using OpenFOAM.Int. J. Heat Fluid Fl.672017, 2742back to text
 61 articleA twophase mixture theory for the deflagrationtodetonation transition (DDT) in reactive granular materials.International journal of multiphase flow1261986, 861889back to text
 62 articleNumerical simulations of flow and heat transfer in a wallbounded pin matrix.Flow, Turbulence and Combustion10412020, 1944HALDOIback to text
 63 proceedingsS.S. BenhamadoucheR.R. HowardR.R. ManceauProc. 15th ERCOFTAC (SIG15)/IAHR Workshop on Refined Turbulence Modelling.EDF Chatou, France2011back to text
 64 articleHIFUinduced cavitation bubble cloud dynamics and its role in model kidney stone erosion.Bulletin Am. Phis. Soc.2022back to text
 65 inproceedingsDevelopment of a hybrid RANSLES model based on temporal filtering for natural convection flows.WCCM  14th World Congress in Computational Mechanics, ECCOMAS Congress 2020Virtual, FranceJanuary 2021HALback to textback to text
 66 articleAnisotropic Organised Eddy Simulation for the prediction of nonequilibrium turbulent flows around bodies.J. Fluid Struct.2482008, 12401251back to text
 67 articleCavitation in medicine.Interface Focus552015, 20150022back to text
 68 articleA compressible multifluid system with new physical relaxation terms.Annales Scientifiques de l'École Normale Supérieure5222019, 255295back to text
 69 articleA low Mach correction able to deal with low Mach acoustics.Journal of Computational Physics378February 2019, 723759HALDOIback to text
 70 miscThe ORACLES database.This experimental database hosted by Zenodo gives access to both the processed and the raw (instantaneous) velocity data measured by 2component laser Doppler velocimetry (1point and 2point measurements) on the ORACLES test facility.August 2022HALDOIback to text
 71 articleA new partially integrated transport model for subgridscale stresses and dissipation rate for turbulent developing flows.Phys. Fluids170651062005, 119back to text
 72 articleLargeeddysimulationbased analysis of Reynoldsstress budgets for a round impinging jet.Physics of Fluids3311November 2021, 115109HALDOIback to text
 73 articleClosure laws for a twofluid twopressure model.Comptes Rendus Mathematique334102002, 927932back to text
 74 articleRecent improvements in the Zonal Detached Eddy Simulation (ZDES) formulation.Theor. Comput. Fluid Dyn.2662012, 523550back to text
 75 articleAll speed scheme for the low Mach number limit of the isentropic Euler equations.Communications in Computational Physics1012011, 131back to text
 76 articleAn elliptic blending differential flux model for natural, mixed and forced convection.International Journal of Heat and Fluid Flow632017, 15HALDOIback to text
 77 bookTheory of multicomponent fluids.135Springer Science & Business Media2006back to text
 78 phdthesisDevelopment of a hybrid RANSLES model for the prediction of unsteady loads at the wall.Université de Pau et des Pays de l'AdourNovember 2020HALback to textback to text
 79 inproceedingsA new formulation of hybrid temporal largeeddy simulation.ETMM 2021  13th International ERCOFTAC symposium on engineering, turbulence, modelling and measurementsRhodes / Virtua, GreeceSeptember 2021HALback to text
 80 articleDevelopment and Validation of a new formulation of Hybrid Temporal Large Eddy Simulation.Flow, Turbulence and Combustion1082022, 42HALDOIback to textback to text
 81 articleA multiphase irreversiblecompaction model for granularporous materials.Continuum Mech. Thermodyn.34.12022, 217241back to text
 82 inproceedingsEtude CFD de l'impact des conditions d'injection pour un stockage thermocline en eau.SFT 2022  30ème Congrès de la Société Française Thermique SFTValenciennes, FranceMay 2022HALback to text
 83 articleRungeKutta discontinuous Galerkin method for the approximation of Baer and Nunziato type multiphase models.Journal of Computational Physics231112012, 40964141back to text
 84 articleProperties of the hybrid RANS/LES filter.Theor. Comput. Fluid Dyn.1742004, 225231back to text
 85 articleOn the behaviour of upwind schemes in the low Mach number limit.Computers & fluids2811999, 6386back to text
 86 articleContinuum theory of ductile rupture by void nucleation and growth: Part IYield criteria and flow rules for porous ductile media.J. Eng. Mater. Technol.9911977, 215back to text
 87 articleNews on BaerNunziatotype model at pressure equilibrium.Continuum Mechanics and Thermodynamics3332021, 767788back to text
 88 articleExtending the bounds of 'steady' RANS closures: Toward an instabilitysensitive Reynolds stress model.Int. J. Heat Fluid Fl.512015, 175194back to text
 89 inproceedingsA buoyancy extension for eddyviscosity models for the natural convection regime.17th European Turbulence Conference (ETC2019)Torino, ItalySeptember 2019HALback to text
 90 inproceedingsSensitization of eddyviscosity models to buoyancy effects for predicting natural convection flows.HEFAT 2019  14th International Conference on Heat Transfer, Fluid Mechanics and ThermodynamicsProc. HEFAT 2019  14th International Conference on Heat Transfer, Fluid Mechanics and ThermodynamicsWicklow, IrelandJuly 2019HALback to text
 91 phdthesisTurbulence modelling of mixed and natural convection regimes in the context of the underhoodspace of automobiles.Université de Pau et des Pays de l'AdourDecember 2020HALback to text
 92 inproceedingsNumerical simulation of a turbulent natural convection flow in a cubic cavity with centrally placed partially heated inner obstacle.3rd highfidelity industrial LES/DNS symp. (HiFiLeD)Brussels, BelgiumDecember 2022HALback to text
 93 articleSteady low Mach number flows: identification of the spurious mode and filtering method.Journal of Computational PhysicsJuly 2022, 111462HALDOIback to text
 94 articleHistotripsy methods in mechanical disintegration of tissue: Towards clinical applications.Int. J. hyperthermia3122015, 145162back to text
 95 articleSpECTRE: A taskbased discontinuous Galerkin code for relativistic astrophysics.Journal of Computational Physics3352017, 84114back to text
 96 inproceedingsContrarotating jets: wake/mixing layer interaction.Proc. 10th ERCOFTAC (SIG15)/IAHR/QNETCFD Workshop on Refined Turbulence ModellingLaboratoire d'études aérodynamiques, UMR CNRS 6609, Université de Poitiers, France2002back to text
 97 articleElliptic Blending Model: A New NearWall ReynoldsStress Turbulence Closure.Phys. Fluids1422002, 744754URL: hal02990466DOIback to textback to text
 98 inproceedingsModélisation des transferts thermiques turbulents (conférence plénière).26e congrès français de thermiquePau, FranceMay 2018HALback to text
 99 inproceedingsModelling of turbulent natural convection (keynote lecture).16th ERCOFTAC SIG15 Workshop on Modelling of wall bounded turbulent natural convectionJozef Stefan Institute (IJS)Ljubljana, SloveniaOctober 2019HALback to textback to text
 100 inproceedingsProgress in Hybrid Temporal LES (invited keynote paper).Papers contributed to the 6th Symp. Hybrid RANSLES Methods, 2628 September 2016, Strasbourg, France137Notes on Numerical Fluid Mechanics and Multidisciplinary DesignSpringer2018, 925URL: hal01391899DOIback to text
 101 articleRecent progress in the development of the Elliptic Blending Reynoldsstress model.International Journal of Heat and Fluid Flow2015, 32HALDOIback to textback to text
 102 inproceedingsTurbulent jet impinging onto a rotating disk: analysis of the RANS results.Proc. 13th ERCOFTAC (SIG15)/IAHR Workshop on Refined Turbulence ModellingTU Graz, Austria2008, URL: hal00385357back to text
 103 articleExtension to various thermal boundary conditions of the elliptic blending model for the turbulent heat flux and the temperature variance.Journal of Fluid Mechanics905A1December 2020, 134HALDOIback to text
 104 inproceedingsModélisation des effets de giration pour les jets en écoulement transverse.Journee thematique SFT : Aerothermique des systèmes propulsifs pour l'aeronautiqueParis, FranceOctober 2022HALback to text
 105 articleContinuum damage theoryapplication to concrete.J. eng. mech.11521989, 345365back to text
 106 inproceedingsAn active hybrid RANS/LES approach for grey area mitigation.DLES13  Direct and Large Eddy SimulationUdine, ItalyOctober 2022HALback to text
 107 articlePressurevelocity coupling allowing acoustic calculation in low Mach number flow.Journal of Computational Physics231162012, 55225541back to text
 108 articleVMS and OESbased hybrid simulations of bluff body flows.Notes on Numerical Fluid Mechanics and Multidisciplinary Design1332016, 293308DOIback to text
 109 articleMultisolid and multifluid diffuse interface model: Applications to dynamic fracture and fragmentation.Journal of Computational Physics2952015, 523555back to text
 110 articleAn experimental database for benchmarking simulations of turbulent premixed reacting flows: lean extinction limits and velocity field measurements in a dump combustor.Flow, Turbulence and Combustion82ACL2009, 155183HALback to text
 111 articleDerivation and Closure of Baer and Nunziato Type Multiphase Models by Averaging a Simple Stochastic Model.Multiscale Modeling and Simulation: A SIAM Interdisciplinary Journal191January 2021, 401439HALDOIback to textback to text
 112 articleHighspeed video microscopy and numerical modeling of bubble dynamics near a surface of urinary stone.J. Acoust. Soc. Am.1462019, 516531back to text
 113 bookletParametric study of the effect of gyration on the flow and heat transfer of multiperforated plates.SOPRANO : Soot processes and radiation in aeronautical innovative combustors. H2020 european project (D3.1)2021back to textback to text
 114 articleA lowMach number fix for Roe's approximate Riemann solver.Journal of Computational Physics230132011, 52635287back to text
 115 inproceedingsMicrobubble generation from condensation and turbulent breakup of sheet cavitation.31st Symposium on Naval Hydrodynamics31st Symposium on Naval Hydrodynamics2016, 1116back to text
 116 articleA multiphase Godunov method for compressible multifluid and multiphase flows.Journal of Computational Physics15021999, 425467back to textback to text
 117 articleDiffuseinterface capturing methods for compressible twophase flows.Annual Review of Fluid Mechanics502018, 105130back to text
 118 articleA low Reynolds number dissipation rate equation model using the dissipation rate tensor equation and ellipticblending equation.J. Mech. Sci. Technol.2552011, 13611371back to text
 119 articleAssessment of ReynoldsStress models for aeronautical applications.International Journal of Heat and Fluid Flow962022HALDOIback to text
 120 inproceedingsReynolds stress RANS models for industrial aeronautical applications.WCCMECCOMAS Congress  14th World Congress in Computational Mechanics and ECCOMAS CongressParis / Virtual, FranceJanuary 2021HALback to text
 121 inproceedingsTurbulence modelling improvements for APG flows on industrial configurations.55th 3AF International Conference on Applied Aerodynamics (AERO2020+1)Poitiers (Virtual), FranceMarch 2021HALback to text
 122 phdthesisImproved ReynoldsStress Modeling for AdversePressureGradient Turbulent Boundary Layers in Industrial Aeronautical Flow.Université de Pau et des Pays de l'AdourJune 2021HALback to text
 123 inproceedingsRANS modelling for temperature variance in conjugate heat transfer.Proc. 5 th World Congress on Mech., Chem., and Material Eng. (MCM'19), Lisbon, Portugal2019back to text