Understanding critical layers in stratified shear flow instabilities: A wave interaction perspective
نویسندگان
چکیده
In this paper we examine the dynamics of unstable critical layers in stratified shear flows. This is done from the framework of the wave interaction theory of shear instabilities, which views instability as arising from the mutual interaction between wave motions that are present in the background shear and density fields. By formulating a simple analytical model of the structure of vorticity within the (continuous) critical layer, we are able to reduce this to an interfacial vortex sheet representation in the far-field that fits naturally into the wave interaction theory. This is applied to describe the physical mechanism of ocean wave generation by wind in an idealised way, though the formulation is applicable to other shear flows in general.
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