Animating turbulent water by vortex shedding in PIC/FLIP

In this paper, we present a hybrid method, which integrates PIC/FL1P and vortex particle methods into a unified framework, to efficiently simulate vortex shedding that happens when fluids flow around internal obstacles. To improve efficiency and reduce the numerical dissipations, we first solve the governing equations on a coarse grid using PIC/FLIP, and then interpolate the intermediate results to a finer grid to obtain the base flow. When the regular particles in PIC/FLIP enter the boundary layer, if the specified conditions are satisfied to cause vortex shedding, they are selected as vortex particles by assigning additional vorticity related attributes. The vortex particle dynamics are controlled by the vorticity form of NS equations, and several efficient methods are proposed to solve them on the finer grid. Finally, the obtained turbulence flow is added to the base flow. As a result, we are able to simulate turbulent water with rich wake details around the internal obstacles.