Wave and water motion analysis using combined boundary element and weighted finite difference method

摘要

In an earlier study, we identified the combined boundary element and weighted finite difference method (WFDM) used to analyze water flow (Kanoh et al. [1]), In order to apply the combined method in our problem the analytical region is divided into four sub-domains. (1) The first and third are irrotational flow domains that exist on both sides of a submerged breakwater, in which the moving boundary technique and the intricate boundary conditions are managed by the boundary-element method (Kanoh et al. [2]). (2) The third is a turbulent flow domain that is located around the breakwater, in which the WFDM provides an accurate solution for the wave and water motion through the openings of the breakwater. (3) The fourth is an extra sub-domain where we set the imaginary boundary and define the passing-through condition of waves. To reproduce the moving free surface in WFDM solutions, first the WFDM grids are changed in the vertical position. However, the velocities of WFDM solutions tend to be diverse in the region near the piston wave-maker. To decrease the divergence, we try to move the WFDM grids both horizontally an4 vertically. Referring to the velocity vectors of the water motion visualized with experimental laboratory models, the effect and accuracy of the alternative hybrid method are estimated.