Stable solid boundary handling algorithm of weakly compressible SPH fluids

Fluid-solid coupling, namely solid boundary handling, has been an important research topic in physically based fluid animation. In this paper, we propose a novel stable and fast solid boundary handling algorithm for weakly compressible smoothed particle hydrodynamics (WCSPH). First, we sample the deformable solids with inner and surface boundary particles in preprocessing stage. Then we compute the relative contributions of boundary particles to their neighboring fluid particles during the density and force computation of SPH fluids. Finally, in order to prevent the penetration artifacts near the fluid-solid interfaces simultaneously, we employ a momentum-conserving velocity-position correction scheme to adjust the velocities and positions of fluid particles whose distances to solid boundaries are smaller than a certain threshold. For improving the efficiency, we entirely implement the unified particle framework on GPUs using CUDA to accelerate the computation of each time step. The results show that the proposed method can handle the stable two-way coupling of WCSPH fluids and deformable solids modeled by fast lattice shape matching (FLSM), and simulate complex phenomena in the coupling, such as non-penetrations, splashes and melting.