A numerical wave tank for nonlinear waves with passive absorption

Abstract

A numerical wave tank with passive absorption for irregular waves is considered in this paper. Waves with spectral shapes corresponding to that of the Mitsuyasu-Bretschneider type are used as the initial condition at one end of the flume. An absorbing boundary is imposed at the other end of the wave flume to minimize reflection. By use of a Lagrangian description for the surface elevation, and finite difference for approximation of the time derivative, the problem is then solved by the boundary element method. The effects of the absorbing boundary are investigated by varying the values of the absorption coefficient μ, and studying the time histories of the surface elevations "recorded" on pre-selected locations.