Wave‐current Models for Design of Marine Structures

Abstract

Modifications to vertical velocity profiles of coastal currents due to surface gravity waves were experimentally and theoretically examined. Results on these modifications were used to develop guidelines for approximating the form of current velocity profiles to be used in predictive models of wave kinematics. The validity of the guidelines was established by comparing the experimental data of wave particle velocities with the theoretical predictions of two wave‐current models which approximate the shear current by: (1) A constant vorticity current; and (2) a uniform velocity over the water depth. The results show that opposing waves decrease the current mean velocity close to the bottom and increase the mean velocity and the current shear near the free surface. Following waves increase mean velocity and velocity gradient of the current, close to the bottom, and might cause the shear at the surface to be negative. Models for constant vorticity and uniform velocity approximations are found to yield accurate predictions of horizontal particle velocities for waves on opposing and following currents, respectively.