a1 Laboratoire de Physique de l'École Normale Supérieure de Lyon, CNRS–Université de Lyon, Lyon 69364, France
a2 Laboratoire M2P2, UMR 6181 CNRS–Universités Aix-Marseille, Marseille 13451, France
a3 Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 01239, USA
a4 Laboratoire des Écoulements Géophysiques et Industriels (LEGI), CNRS, Grenoble 38000, France
We present the results of a combined experimental and numerical study of the generation of internal waves using the novel internal wave generator design of Gostiaux et al. (Exp. Fluids, vol. 42, 2007, pp. 123–130). This mechanism, which involves a tunable source composed of oscillating plates, has so far been used for a few fundamental studies of internal waves, but its full potential is yet to be realized. Our study reveals that this approach is capable of producing a wide variety of two-dimensional wave fields, including plane waves, wave beams and discrete vertical modes in finite-depth stratifications. The effects of discretization by a finite number of plates, forcing amplitude and angle of propagation are investigated, and it is found that the method is remarkably efficient at generating a complete wave field despite forcing only one velocity component in a controllable manner. We furthermore find that the nature of the radiated wave field is well predicted using Fourier transforms of the spatial structure of the wave generator.
(Received August 05 2009)
(Revised April 21 2010)
(Accepted April 21 2010)