Fluid-Solid Coupling Simulation Based On SPH-FEM

The phenomenon of fluid-solid coupling can be seen everywhere in real life.How to simulate it realistically has always been one of the hotspots and difficulties of computer graphics researchers.The research results of fluid-solid coupling simulation have important applications in natural disaster simulation,virtual reality games and special effects of film and animation.The most simulations about fluid-solid coupling are based on particle-based methods,especially the Smoothed Particle Hydrodynamics(SPH)method which is the most widely used.Although the SPH method has significant advantages in simulating large deformation and free surface flow,there is a boundary stretching phenomenon when simulating solids.In addition,most of the current simulations of fluid-solid coupling treat solids as rigid bodies,without considering the interaction of fluids with deformable solids.This paper simulates the interaction between fluid and deformable solid by coupling SPH method and Finite Element Method.The SPH method simulates the fluid domain,and the deformable solid domain is simulated by the Finite Element Method.The FEM method simulates solids with high precision and is easy to handle complex boundaries.More importantly,the FEM is also based on the Lagrangian format,so it is easy to solve in the same time step.In this paper,the SPH-FEM coupling algorithm is used to simulate the fluid-structure coupling.The main work is as follows:(1)The fluid domain is solved and simulated by using the SPH method.Analyze and research the neighborhood particle search algorithms and kernel functions.These affect the accuracy of the algorithm and the efficiency.The motion state of the fluid particles is updated by solving time integration with the leap-frog format.(2)The deformable solids in the scene are analyzed and solved by using the finite element method.Deformation model is established by using strain tensor and strain rate to control the deformation of solids.(3)In order to limit the penetration of fluid particles,a penalty function method is used to apply contact force to particles and solid elements at the boundary.Screening boundary particles is to reduce collision detection and improve computational efficiency.Unified the time step of SPH and FEM.(4)The surface of fluid is reconstructed by using anisotropic kernel function.In contrast to the traditional method,this method can construct more smooth surface of fluid.