Abstract
This paper presents numerical models for wave transformation due to current-depth refraction in cases of both regular and irregular waves. The models are to solve the equations for wave number components and the conservation equation of wave action or wave action spectral density by the combination of the method of characteristics and an interpolation formula. Numerical solution agrees well with the theory in cases where a one-dimensional current exists on a uniform depth or a uniformly sloping bottom. It is also found that the wave height of irregular waves is not amplified by opposing currents as well as following currents and that the model renders a slight overestimation of wave height distribution in the case of opposing currents because of a directional leakage of energy.
