BREAKING AND CASCADE OF INTERNAL GRAVITY-WAVES IN A CONTINUOUSLY STRATIFIED FLUID

The evolution of a few large scale high frequency standing internal wa ves confined to a vertical plane is studied numerically. The growth of nonlinear interactions leads to a transfer of energy toward small ver tical scales and lower frequencies: the result is a steep energy decre ase due to wave breaking. Induced mixing is evaluated. A parametric fo rcing is also introduced in order to compare with laboratory experimen ts. Wave breaking also occurs but as opposed to the unforced case diff erent phases are next observed: internal wave growth due to constructi ve forcing alternate with energy decrease.