Eulerian numerical modelling of fluid-structure interactions : application to the simula- tion of biological capsules in flow
A capsule is composed of a membrane, which is a closed surface with elastic properties protecting an internal fluid. The capsule size varies between a few millimeters and a few microns. In all the applications, capsules are immersed in an external fluid. They are used in many fields such as cosmetics, bioengineering or medicine. Many pathologies, like cancers and infections, can alter cell size and change their mechanical properties. Sorting cells according to their characteristics opens the way to detect and isolate infected cells. In addition to the financial cost, designing new microfluidic devices for each application is currently time consuming as it requires multiple experiments to find the optimal device. This is precisely the purpose of the present project, its goal is to develop an original HPC numerical tool for fluid-structure interaction to simulate the behavior of capsules in their environments, and to use it to design microfluidic systems dedicated to enrichment and sorting of capsules suspensions. In order to meet this objective, it is proposed to use completely Eulerian models of fluid / structure interaction that take into account the inertia, complex geometries and large deformations of the structure. However, two numerical locks have been identified for our application: increasing physical simulation time for fluid-structure interaction simulations when membrane stiffness is important and taking into account contacts in particle/particle and particle/walls interactions. In order to remove these locks, it is proposed to develop new semi-implicit schemes fully Eulerian and to implement Eulerian models of contacts.The numerical schemes will be implemented in the massively parallel, open-source code Notus developed in the I2M Laboratory of Bordeaux. It is also proposed in the project to enrich the capsule model with an elastic nucleus. This validated numerical tool will allow us to optimize microfluidic devices for enrichment and sorting of diluted or concentrated suspensions.