A numerical study of conjugate flows and flat-centred internal solitary waves in a continuously stratified fluid.

摘要

In this thesis a theoretical model describing the limiting flow structure in the centre of a fully nonlinear, flat-centred internal solitary wave in a fluid of finite depth H has been developed using the conjugate flow concept. The conjugate flow solution gives the vertical structure of the isopycnal displacement and the fluid velocity at the centre of a flat-centred internal solitary wave as well as the propagation speed of the wave. The mode-1 internal solitary waves are calculated in a continuously stratified fluid given by hyperbolic tangent density profiles with one or two pycnoclines. Solutions obtained with and without the Boussinesq approximation are compared. The non-Boussinesq results are almost identical with the Boussinesq results if the surface to bottom density difference is 4% or less unless the pycnoclines have a thickness comparable to the total fluid depth.; For density stratifications with a single pycnocline, conjugate flow solutions are obtained when the pycnocline is not too close to the boundary.; For stratifications with two pycnoclines multiple conjugate flow solutions may exist. (Abstract shortened by UMI.)