Dr. Keshav J. Raja from the University of Grenoble

February 28th 2018, 3:30 pm

Forcing of mean flows by the reflection of three-dimensional internal wave beams


Internal waves play an important role in many processes in oceans. The interaction between internal waves and ocean topography has been an active field of research for long. Yet there are many questions remaining on the topic. I am going to present our work on a specific process namely, the reflection of 3D internal wave beams on a slope, showing results from laboratory experiments and numerical simulations. The reflection of plane internal waves or two-dimensional internal wave beams on a slope has been studied a lot in the past. However, the case of a finite width three-dimensional internal wave beam has gained attention only very recently. In the case of reflection of three-dimensional internal wave beams, a strong mean horizontal flow is found to be induced by the wave beam, which perturbs the wave field and weakens the second harmonics. The generation and growth of this wave-induced mean flow is examined in detail using results from experiments and three-dimensional numerical simulations. Furthermore, the effects of wave parameters such as wave amplitude and wave beam width, and the influence of fluid viscosity on the induced mean flow are examined. Finally, the forcing of mean flow by a reflecting inertia-gravity wave beam is also examined for various values of Coriolis frequencies.