Abstract
This paper presents a numerical model of nearshore currents taking into account the wave nonlinearity, in which a cnoidal wave theory is used for the estimation of wave characteristics. The model is applied to the computation of wave transformation and nearshore currents across the surf zone on a uniformly sloping beach and on model topographies, and the results are compared with those obtained by a linear model. The comparison shows that the wave nonlinearity has a strong influence on the offshore distributions of wave height, wave direction and mean water level, and the peak position of longshore currents, but that it does not have much effect on the longshore current profile itself. It is also found that the wave nonlinearity acts to suppress the formation and growth of nearshore circulation currents.
