On wave-current interaction in deep and finite water depths

Interaction of linear and nonlinear, long-crested waves with currents in deep and finite water depths is studied by use of the computational fluid dynamics approach. Various wave conditions are considered by systematically changing the wave height and the wavelength. Several current profiles are studied as polynomial functions of water depth following the profiles and magnitudes of the available ocean current data. Both following and opposing currents are considered, and in total, 26 wave-current configurations are investigated. The two-dimensional study is carried out computationally by solving the Navier-Stokes equations for a laminar flow. The governing equations are solved by use of the finite volume approach in an open-source computational fluid dynamics package, namely OpenFOAM. Modifications are made to an existing wave-making toolbox, waves2Foam, to generate combined nonlinear waves and currents in deep and finite waters. Results of the numerical wave-current tank are compared with the existing laboratory measurements and overall very good agreement is observed. Discussion is provided on the effect of these currents on the change of the wave field, including quantitative change of the surface elevation, wave profile, pressure distribution, and fluid particle velocity of waves. Overall, it is observed that opposing current has a remarkable impact on the wave field, and the particle velocity and wave height are affected the most from the presence of the current.