A Numerical Model of Nearshore Irregular Wave Based on Fully Nonlinear Boussinesq Equations

摘要

In this research, a unidirectional irregular wave-making method is proposed by combination of the source function wave-making theory and Longuet-Higgins et al. (1961)Es irregular wave concept. As a consequence a numerical wave model is established on the basis of the fully nonlinear Boussinesq equations. By using the irregular wave model, numerical tests are performed. The method of spectral evaluation from autocorrelation function is used in the analysis of the numerical results. It is found from the analysis results that for small value of h/L_0, the value of simulated H_(1/3) is closer to the input one, while for larger value of h/L_0, the value of H_(1/3) is slightly larger than that of the input value. The reason for this is believed to be due to the existence of some high frequency components in the irregular waves. The analysis results also show that in the method of spectral evaluation from autocorrelation function, the time interval delta t, the number of wave components m with different frequencies and the total number of the samples of the time series of water surface elevation N affect one by another and it is further found that in the case of delta t being equal to T_(1/3)/50, the result of spectra from the evaluation method is consistent with the target spectra when m evaluated in the range of N/10 -