A Contact Proxy Splitting Method for Lagrangian Solid-Fluid Coupling

Fig. 1. Kick water. Our method accurately captures the complex interactions between the water, the multi-layer skirt, and the mannequin body without any interpenetration as the mannequin wearing the skirt kicks in a swimming pool and sends water flying.

We present a robust and efficient method for simulating Lagrangian solidfluid coupling based on a new operator splitting strategy. We use variational formulations to approximate fluid properties and solid-fluid interactions, and introduce a unified two-way coupling formulation for SPH fluids and FEM solids using interior point barrier-based frictional contact. We split the resulting optimization problem into a fluid phase and a solid-coupling phase using a novel time-splitting approach with augmented contact proxies, and propose efficient custom linear solvers. Our technique accounts for fluids interaction with nonlinear hyperelastic objects of different geometries and codimensions, while maintaining an algorithmically guaranteed non-penetrating criterion. Comprehensive benchmarks and experiments demonstrate the efficacy of our method.