Wave-current interaction within and outside the bottom boundary layer

This paper reviews the state-of-the-art as perceived by the Wave-Current Interaction (WCI) group which forms part of the MAST G6M Coastal Morphodynamics project, and includes some new results arising out of that project. Those processes which affect the vertical profiles of current and wave kinematics, and the bed shear-stresses, are discussed, but “horizontal” processes such as refraction of waves by currents, and generation of longshore currents, are not included. Among the group's conclusions are recommendations for the calculation of wave-induced bottom orbital velocities with and without WCI, and direct parameterisations of the bed shear-stresses produced by WCI. The latter is the results of a comprehensive intercomparison of WCI boundary-layer models and data. The results are aimed at aiding the formulation of numerical models of coastal morphodynamics.