Non-smooth contact models

Corresponding publications: [A5, P6, Preprint1, Preprint2]

• Inelastic contacts, with or without friction
• Non-smooth contact models (non-smooth convex analysis framework)
• Stable algorithms based on constrained convex optimization problems
• Convergence results

Non-spherical particles. [Faure, Gouarin, Lefebvre-Lepot]	Ellipsoidal particles, inelastic contact without friction. [Bloch, Lefebvre-Lepot, P6]

SCoPI software

Corresponding publications: [A12, P4]

• Simulation of Collections of Particles in Interaction
• Stable algorithms for inelastic or gluey contact models
• Non-spherical particles
• Macroscopic studies of granular media (inter-disciplinary work)
• C++ code
• Software webpage

Random packing for nonconvex particles. [Faure, Lefebvre-Lepot, Semin, P4]	Flow around a sphere moving into a grain cloud. [Seguin, Lefebvre-Lepot, Faure, Gondret, A12]

Coupling fluid/particles solvers and contact models

Corresponding publications: [A6, A8, A10, P1, P2, C2, C3]

• Fictitious domain solver using a penalty method to deal with the rigid constraint in the particles
• Coupling with the non-smooth contact models developped for granular flows
• Application to vesicle simulation
• ANR RheoSuNN : coupling SCoPI software with the fluid solver CAFES

Vesicle in shear flow: Tank-treading motion. [Ismail, Lefebvre-Lepot, A10]	Vesicle in shear flow: Tumbling motion. [Ismail, Lefebvre-Lepot, A10]

Numerical methods to deal with the hydrodynamic singularity produced by close particules (lubrication phenomenon)

Corresponding publications: [A4, A11, A15, P5, C2]

• Development of a "gluey" contact model, taking lubrication into account
• Development of an accurate numerical method to solve the fluid/particle problem, using an explicit asymptotic expansion of the solution in the narrow gap between close particules

Gluey contact model. [Lefebvre-Lepot, A4]	Singularity correction. [Lefebvre-Lepot, Nabet, A15]

Development of tools for boundary finite element methods (BEM) for Stokes

Corresponding publications: [A13, A14]

• Fast method (SCSD) to compute the full matrix/vector product
• Precise computation of the singular integrals
• Application to rigid particles immersed in a Stokes fluid

Spheroid in a tube. [Alouges, Lefebvre-Lepot, Sellier, A14]	Cluster of spheroidal particles. [Lefebvre-Lepot]

Towards marcroscopic description of suspensions.

Corresponding publications: [A1, A7]

• Apparent viscosity, numerical investigation, link with microscopic configuration
• One dimensional macroscopic model for lubricated particles, homogeneization-like result.

Apparent viscosity for different configurations. [Lefebvre-Lepot, Maury, A1]	1d macroscopic model for lubrication. [Lefebvre-Lepot, Maury, A7]

Stokesian micro-swimmers

Corresponding publications: [A2, A3, A9, A16, A17, P3, C1]

• Existence of strokes producing a given displacement
• Computation of the stroke that require the minimal energy
• General control and optimal control framework
• Structure of the optimal strokes

Swimmers made of spheres with controllable arms in 1d, 2d and 3d. [Alouges, DeSimone, Heltai, Lefebvre-Lepot, Merlet, A2, A9, P3, C1]