A fully Eulerian lattice Boltzmann simulation of multi-soft-body fluid–structure interaction

We introduce a new Eulerian simulation method for simulating a fluid interacting with finite-strain deformable solids. The fluid is simulated using the lattice Boltzmann (LB) method on a fixed grid, and the solids use the reference map technique (RMT) that allows finite-strain elasticity to be modeled using the same grid as the fluid. By using a unified grid for both the fluid and solid phases, the interphase coupling is greatly simplified. The new hybrid simulation method, the LBRMT, inherits the attractive features of the LB method to simulate a quasi-incompressible fluid in a simple and parallelized fashion. Since our hybrid method only has one global velocity field, it is well-suited for modeling complex geometries and multi-body contact. We demonstrate our method with examples of many deformable solids sedimenting and floating, bending and twisting of flexible rotors, and collective motion of actuated microswimmers.