A Numerical Model of Nearshore Currents Based on a Finite Amplitude Wave Theory

A numerical model of wave-Induced nearshore currents taking into account the finite amplitude effect is developed, with a cnoidal wave theory used for the estimation of wave characteristics. The model is applied to the computation of wave transformation and nearshore currentson uniformly sloping beaches and on two-dimensional model topographies. The comparison with the results obtained by a linear model shows that wave nonlinearity has a strong influence on wave transformation in shoaling water and in the surf zone and on the strength of nearshore circulation, but that it does not have much effect on the longshore current profile. Moreover, the validity of the present model is supported by the quantitative agreement with the experiment for wave height variations, and the qualitative correspondence with the experiment for mean water level variation and longshore currents and the observation for nearshore currents.