We consider the generation and evolution of finite amplitude internal waves over, and downstream of, small-amplitude topography. We demonstrate that in addition to a large amplitude, non-hydrostatic wave trapped over the topography, a finite amplitude wavetrain of Poincaré waves is generated. This wavetrain is nearly hydrostatic over the majority of its extent, but can lead to the generation of non-hydrostatic undular bores, weak shear instability, and large secondary solitary-like waves downstream. The secondary waves are non-hydrostatic, and unlike the undular bores, achieve steady state. For parameters corresponding to a high latitude, coastal ocean secondary waves are generated well over 100 km downstream of the topography. The hydrostatic Poincaré waves thus serve as a bridge for strong energy transfer from the forcing region to distant regions downstream.
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2012
American Institute of Physics
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