The paper presents improved Incompressible SPH (ISPH) methods for prediction of wave impact pressure on a coastal structure. The first improvement is the employment of a corrective function for enhancement of angular momentum conservation in a particle-based calculation. The second improvement is the application of a higher order source term derived based on a higher order differentiation to provide a less fluctuating and more accurate pressure calculation. The enhanced performance of improved ISPH methods in prediction of wave impact pressure has been shown by simulating a dam break with impact and a flip-through impact.
Past failures of coastal structures indicate that some of the conventional design methods based on solely static or quasi-static analysis are not entirely reliable. Furthermore, both theoretical (e.g. Cooker and Peregrine, 1994) and experimental (e.g. Hattori et al., 1994) studies highlight the essential role of the so-called wave impact pressure in design of coastal structures. Thus, development of reliable design tools for prediction of wave impact pressure becomes indispensable. The numerical models developed for calculation of wave impact pressure are mainly based on the Navier-Stokes equation which describes the motion of an incompressible, viscous fluid. In case of grid-based Eulerian solvers of Navier-Stokes equation a mathematical treatment of free surface is required. Christakis et al. (2002) and Kleefsman et al. (2005) employed refined versions of Volume Of Fluid (VOF) method (Hirt and Nichols, 1981) to treat the free surface in their wave impact calculations. Nevertheless, VOF-based models have the drawback of numerical diffusion arising from fixed-point interpolations of advection terms in both VOF function transport equation and Navier- Stokes momentum equation. A few sophisticated schemes such as the CIP method (Yabe et al., 2001) have been proposed to attenuate the numerical diffusion in an Eulerian grid-based calculation. Hu and Kashiwagi (2004) applied the CIP method in their grid-based wave impact calculations and obtained quite satisfactory results.
