Eulerian simulation of fluid–structure interaction in bioinspired complex suspensions and locomotion

We present a computational method to simulate fluid–structure interaction (FSI) based on the lattice Boltzmann reference map technique (LBRMT). The LBRMT uses the reference map technique (RMT) to model large deformations of finite-strain solids on one fixed grid in an Eulerian framework, and couple fluids onto the same computational grid with the lattice Boltzmann (LB) method. In addition to the tractable features of Eulerian simulation and parallelizable fluid update of the LB method, the LBRMT is apt at simulating multi-body contact of complex geometries since it uses one global velocity field for both phases. Another integral part of our method is a new and simple implementation to model moving deformable boundary conditions for FSI problems in the LB method. Through diverse LBRMT simulations, we highlight its biological applications in sedimentation and flotation, flexible rotors, actuated microswimmer, and its potential to understand the spatiotemporal dynamics of collective motion.