Towards real-time simulation of physically realistic pressure applied to submerged bodies using explicit and semi-implicit SPH algorithms

This paper compares different algorithms using the Smoothed Particle Hydrodynamics (SPH) discretization to provide realistic simulations of submerged bodies in water. Two different techniques for handling fluid-solid boundaries (mirroring and Shepard extrapolation) and two different pressure calculation methods (pressure projection and state equation) are investigated. The first contribution of this paper is to propose a test case with a submerged sphere in a water tank, in which the evolution of fluid pressure over depth is watched to compare the accuracy of the boundary handling techniques and the pressure calculations methods. The second contribution of this paper is to evaluate the accuracy of the solvers in dynamic cases, looking at the evolution of the pressure over time, the evolution of sphere speed over time and comparing with an analytical falling speed based on added mass and/or velocity damping. Third contribution of this paper is to evaluate the solvers using performance metrics based on computational time and time step counts. The results showed that the solver using pressure projection and Shepard extrapolation have reliable accuracy and good computational efficiency and might be a favored approach towards achieving accurate real-time simulation of underwater vehicles.