A modified approach to wavemaker modeling for high-order spectral numerical wave tanks

Abstract

In this study, an enhanced novel numerical wave tank (NWT), based on the high-order spectral (HOS) method, is established to simulate the propagation of fully nonlinear water waves. A fundamental issue of the HOS-NWT approach is the wave generation problem, which is accounted for using an additional potential concept. We propose a modified wavemaker model by feeding wave properties from the tank bottom to the instantaneous wave surface, according to a chosen wave theory at the tank entrance. Gravity water waves at intermediate and shallow water depths are adopted in this study to verify the stability, efficiency, and accuracy of the modified and conventional methods for wave generation, by comparison with stream function solutions. The results of both methods for in-silico waves are almost identical to the stream function solutions for intermediate water waves. However, the modified model performs better than the conventional one for long shallow water wave simulations. Through Fourier analysis, evident nonlinear characteristics of the time series of the wave elevations are confirmed. The modified HOS-NWT is also extended to investigate nonlinear wave–wall interactions, and satisfactory agreement is achieved with the numerical Fourier solutions.