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.

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]