A hybrid Eulerian-Lagrangian simulation framework for heterogeneous soft structures operating in fluids

Structures encountered in ­biolog­ical and robotic domains are often con­stituted of slender elastic elements that are distributed, heterogeneous, and hierarchically ­organized. Their interaction with surrounding fluids is computationally challenging and expensive to resolve. Here, we mitigate these issues via a hybrid Eulerian-Lagrangian algorithm that combines Cosserat rod theory with vortex methods and immersed boundary techniques. The resulting elastohydrodynamic solver is tested against a battery of benchmarks, and further extended to the context of muscular hydrostats, multi-body contact, magnetic actuation, and immersed soft robot design.