Analysis of vertical profiles of mean velocity, shear stress and turbulent viscosity in a wave-current environment through RANS numerical simulations

Abstract

The nearshore hydrodynamics and coastal circulation result from the contribution of a variety of phenomena (large scale circulation currents, tidal effects, waves, wind action, etc.) which have complex physical interactions with different scales. Among these interactions, we focus here on the interaction between waves and currents, especially when the current presents a strong shear over the water depth. In the present work, the evaluation and analysis of wave-current interactions is made through numerical simulations based on Reynolds Averaged Navier-Stokes (RANS) equations, applied to the modeling of the complete flow motion, namely waves and currents simultaneously (i.e. without decoupling the two phenomena). The advanced CFD solver code_Saturne (ARCHAMBEAU et al., 2004) is used for this purpose. Numerical results are compared with experimental data from UMEYAMA (2005). Four different wave heights and wave periods for each case of (i) only waves, (ii) waves following currents and (iii) waves opposing currents are tested. A detailed study of the mean horizontal velocities, shear stresses and turbulent viscosity vertical profile changes when waves and currents interact is presented.