CHANGES OF THE MEAN VELOCITY PROFILES IN THE COMBINED WAVE-CURRENT MOTION DESCRIBED IN A GLM FORMULATION

The generalized Lagrangian mean (GLM) formulation is used to describe the interaction of waves and currents. In contrast to the more convent ional Eulerian formulation the GLM description enables splitting of th e mean and oscillating motion over the whole depth in an unambiguous a nd unique way, also in the region between wave crest and trough. The p resent paper deals with non-breaking long-crested regular waves on a c urrent using the GLM formulation coupled with a WKBJ-type perturbation -series approach. The waves propagate under an arbitrary angle with th e current direction. The primary interest concerns nonlinear changes i n the vertical distribution of the mean velocity due to the presence o f the waves, but modifications of the orbital velocity profiles, due t o the presence of a current, are considered as well. The special case of no initial current, where waves induce a so-called drift velocity o r mass-transport velocity, is also studied.