Wave Impact Simulations by an Improved ISPH Model

Abstract

This paper presents an improved incompressible smoothed particle hydrodynamics (ISPH) method for wave impact applications. In most conventional ISPH techniques the source term of the pressure Poisson equation (PPE) is usually treated by either a density invariant or a velocity divergence-free formulation. In this work, both the density invariant and velocity divergence free formulations are combined in a weighted average form to determine the source term. The model is then applied to two problems: (1) dam-breaking wave impact on a vertical wall and (2) solitary wave run-up and impact on a coastal structure. The computational results have indicated that the combined source term treatment can predict the wave impact pressure and force more accurately compared with using either formulation alone. It was further found that depending on the application case, the influence of the density invariant and divergence-free parts could be quite different. For the more violent wave impact case, the divergence-free part played a more prominent role in ensuring accurate force simulations, while in less violent wave impact cases, the density invariant part seems to be more significant. A systematic parametric study has shown that the weighting coefficient in the PPE source term is independent of particle spacing under various wave impact situations. Also, a close relationship has been found between the ratio of flow height to length scales