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Internal wave reflection in uniform shear
Author(s) -
Sutherland B. R.
Publication year - 2000
Publication title -
quarterly journal of the royal meteorological society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.744
H-Index - 143
eISSN - 1477-870X
pISSN - 0035-9009
DOI - 10.1002/qj.49712657013
Subject(s) - wave packet , physics , internal wave , amplitude , mechanical wave , mechanics , shear flow , longitudinal wave , wave propagation , love wave , dispersion (optics) , reflection (computer programming) , surface wave , wave shoaling , mean flow , gravity wave , classical mechanics , turbulence , optics , quantum mechanics , computer science , programming language
If nonhydrostatic internal waves are of sufficiently large amplitude, they undergo significant dispersion due to interactions between the waves and wave‐induced mean flow. The effect of these interactions is investigated for internal waves propagating upward in a uniformly stratified Boussinesq flow with uniform shear. The sign of the shear is established so that the wave intrinsic frequency increases as the wave packet propagates upward; hence linear theory predicts that the waves should reflect at some level. Fully nonlinear numerical simulations of two‐dimensional wave packets are performed to study the wave‐packet evolution as a function of the initial amplitude and spatial extent of the wave packet. It is shown that if the waves are horizontally periodic, and of sufficiently large amplitude, momentum is permanently deposited to the mean flow at altitudes near, but below, the reflecting level predicted by linear theory. If the waves are horizontally compact, the waves propagate upward well above the reflection level.