Interaction of short-crested random waves and large-scale currents

Abstract

Methods are outlined for determining the transformations to directional wave spectra induced by large-scale currents. The problems considered are those where waves move from quiescent water on to a current, or from one current region to another. Situations involving wave generation on currents are not discussed. The principle of wave action conservation is used to relate the wave energy densities in the two regions, and an equilibrium range constraint is applied to the high frequency tail of the transformed spectrum in instances where wave action is not conserved and energy is dissipated by wave breaking. Examples are presented which highlight how current-induced wave refraction and energy dissipation may have important consequences for the transformed spectrum.