Generation of internal gravity waves by vortex disturbances in a shear flow

Abstract

A mechanism of internal gravity wave generation by eddy perturbations in a horizontal flow with a vertical shear has been investigated. It is assumed that a shear flow is localized in the atmospheric boundary layer with neutral stratification, over which there is a semibounded stratified layer moving at a constant velocity. It is shown that the propagation of vortex perturbations in the boundary layer is inevitably accompanied by wave generation. On the basis of a linearized system of hydrodynamic equations, an integro-differential equation is formulated for finding wave characteristics. A wave field excited by a vortex perturbation with an initial singular vorticity distribution is studied. Numerical estimates are obtained for the vertical energy flow density vector component characterizing the wave energy transport to the upper atmosphere.