A numerical study of the transformation of water waves generated in a wave flume

This paper is concerned with the transformation of water waves generated in a numerical wave flume. To set up the numerical wave tank, the non-periodic spectral method is used to solve potential flow equations incorporated with fully nonlinear free-surface boundary conditions and the wavemaker boundary condition. The flume is employed to simulate the transformation of water waves with different steepness and wavelength. The calculation results of the free-surface elevation and the corresponding amplitude wave spectrum are compared with the linear wave solutions and the analytical solutions. The result of the investigations is that short waves agree well with the linear solutions, whereas the long waves with limited Ursell numbers are consistent with the analytical solutions. Physical experiments are conducted in a wave flume to verify the numerical scheme. Good agreement between the experimental and the numerical results is obtained. The time-frequency information of waves is also investigated based on the wavelet transform. The numerical results show that short waves with smaller Benjamin-Feir index (BFI) are more stable than long waves with larger BFI in finite wave depth.