ON WAVE CURRENT INTERACTION IN A TURBULENT BOUNDARY-LAYER

A two-equation turbulence model is used to study the interaction of waves and currents in a turbulent bottom boundary layer beneath a progressive water wave. Attention is restricted to flows for which the steady part of the velocity is comparable in magnitude to the orbital velocity associated with the wave motion. The governing equations are treated asymptotically for the case ∊-1, β-l, where ∊ is a measure of nonlinearity and β is the square root of a characteristic drag coefficient. It is shown that the steady velocity at the outer edge of the boundary layer satisfies a logarithmic law with an apparent roughness length in excess of the physical bottom roughness. The results of the calculation are shown to agree well with observations. © 1990, Taylor & Francis Group, LLC. All rights reserved.