Source Generation of Fully Nonlinear Waves In NWT With a 3D HOBEM

Teng, Bin (Dalian University of Technology) | Ning, Dezhi (Dalian University of Technology)

OnePetro 

ABSTRACT:

A time-domain higher-order boundary element method (HOBEM) is used to simulate the linear and fully nonlinear waves in a threedimensional numerical wave tank (NWT). In order to eliminate reflective waves at the incident boundary and output boundaries, damping layer combined with a nonreflective wave generator, which is composed a series of vertically aligned point source in the computational domain, is applied. The governing equation is solved at each time step by using Rankine sources distributed on all the boundaries. Based on the image theory, a new Green function is applied in the whole fluid domain so that the two lateral surfaces and bottom are excluded. Numerous numerical experiments, on linear and fully nonlinear wave propagation in a wave tank with and without fully reflective wall, demonstrate that the present approach is effective in generating an arbitrary wave profile without reflection not only at the open boundaries but also at the wave generator. It is furthermore shown that scattered waves can pass through the area of generation without significant reflection and the process of generation is not affected by the scatted waves.



INTRODUCTION

With the increasing use of numerical techniques and computers during the past two decades, it is possible that the numerical wave tanks are used to investigate wave interaction with structures and the considerable efforts have been devoted to developing increasingly accurate and efficient numerical wave tank to investigate various fully nonlinear water wave problems at sea. Such numerical results have been shown to model the wave propagation and overturning in deep water (Dommermuch et al., 1988), wave shoaling up to breaking over slopes (Grilli et al., 1994), wave loads on objects (Zhang et al., 1996; Boo and Kim, 1997; Kashiwagi, 1996) and floating body motions (Isaacson,1982; Kashiwagi, 1998) etc.