Section: New Results

Assessments of models by means of experimental data

Hydrodynamics and biology coupling in the context of algae growth

Participants : Marie-Odile Bristeau, Jacques Sainte-Marie.

In collaboration with BIOCORE (especially O. Bernard) in the framework of the IPL Algae in Silico.

Hydrodynamics in a high rate production reactor for microalgae cultivation affects light history perceived by the cells. The interplay between cell movement and medium turbidity leads to a light pattern forcing photosynthesis dynamics. The purpose of this multidisciplinary downscaling study is to reconstruct single cell trajectories in an open raceway and experimentally reproduce such high frequency light pattern to observe its effect on growth. We show that the frequency of such a realistic signal plays a determinant role in the dynamics of photosynthesis. This study highlights the need for experiments with more realistic light stimuli in order to better understand microalgal growth at high cell density.

2D Drucker-Prager and μ(I) granular flow model

Participant : Anne Mangeney.

In collaboration with François Bouchut, Ioan Ionescu, Alexandre Ern, Christelle Lusso and Nathan Martin.

We developped 2D (horizontal/vertical) models of granular flows solving the yield behaviour of Drucker-Prager type laws using either a duality method or a regularization method. We included the effect of the lateral wall friction and get very good agreement with laboratory experiments of granular collapses over horizontal and inclined planes.

Analytical and numerical description of the static/flowing interface deduced from 2D Drucker-Prager model

Participant : Anne Mangeney.

In collaboration with François Bouchut, Alexandre Ern and Christelle Lusso.

We proposed analytical and numerical solution of the static/flowing interface and compared it with laboratory experiments of granular flows. Our study show how the static/flowing interface dynamics depends on the slope, friction angle, viscosity and normal velocity profiles.

Seismic inversion and numerical modelling of the force generated by landslides on the topography or by iceberg calving

Participant : Anne Mangeney.

By inverting the long period seismic signal to recover the force generating seismic waves and simulating this force with mechanical models of granular flows, we can provide a unique constraint on the dynamics of the phenomenon at stake and on its characteristics.

Data assimilation

Participants : Sebastian Reyes-Riffo, Julien Salomon.

In collaboration with Felix Kwok.

Taking advantage of a PROCORE-FRANCE/HONG KONG grant obtained in the latter spring, we work on a time-parallelization strategy for an assimilation algorithm. The target application also deals with wave energy: we aim at forecasting in real-time the characteristics of the wave coming on an extracting device, in order to adapt it in a continuous way.