Irregular wave Refraction Due to Current

Abstract

The phenomenon of wave refraction due to current is an important factor in the longshore current generation and the wave transformation in the vicinities of narrow strait and river mouth. The existing numerical models of wave refraction due to current are all for regular waves. A numerical model is proposed for the computation of the change of the directional spectral density of irregular waves due to current‐depth refraction. The wave action equation is applied as the basic equation, in which the wave direction is introduced as the fourth independent variable. Several sample computations show that this model can explain the change of the directional spectra due to current. It is found that the significant wave height changes more rapidly than that of the corresponding regular waves having the same wave height, period and direction as those of the irregular waves. The change of a mean wave direction of the irregular waves is different from that of the corresponding regular waves.