Some aspects of the behavior of high order mode internal gravity waves on interfaces with finite thickness

The role of interface thickness on the propagation of high order internal wave modes is examined using simple analytical models for an unmixed, thick interface and one that has been vigorously mixed. It is shown that for the unmixed case, a local maximum in wave speed occurs as the interface grows from zero thickness, but that only for mode-one waves does the maximum point occur within areas of practical significance. When these models are applied to three wave resonant interactions, it is found that vigorous mixing will augment energy transfer rates when the interface thickness surpasses a certain value.