GEOMETRY AND ENERGETICS OF BEAMS OF INTER NAL WAVES

The Boussinesq approximation is used to investigate the propagation an d reflection of beams of internal gravity waves in a viscous exponenti ally stratified fluid. A propagator is constructed that relates the ve rtical displacements in arbitrary transverse sections of a propagating or a reflecting beam. On the basis of the propagator, the Huygens pri nciple is formulated for wave packets. The energy density per unit len gth and the energy flux in a beam are calculated. The coefficients of energy losses, a fraction of the energy of an incident beam transferri ng to the boundary flow, are obtained. Under typical laboratory condit ions, they prove to be about 2% for a vertical wall, 60% for a horizon tal wall, and 20% for intermediate positions of the reflecting rigid p lane.