Bruce R Sutherland, University of Alberta
One component of the Reynolds stress measures the vertical flux of horizontal momentum across a vertical level. For small-amplitude internal waves, it also measures the flux of pseudomomentum (Scinocca & Shepherd, JAS, 1992) or, equivalently, the momentum associated with the wave-induced mean flow. Fully nonlinear numerical simulations reveal that the order amplitude-squared formula for the pseudomomentum per unit mass captures the wave-induced mean flow with good accuracy even for waves close to overturning amplitudes. This will be demonstrated in two cases. In one, internal waves are generated from a non-uniformly stratified shear flow and pseudomomentum is used to diagnose both momentum transport and mixing. In another, a moving heat source in stationary, uniformly stratified fluid creates internal waves and it is shown, as a consequence of pseudomomentum conservation, that this results in the generation of a localized jet flow near the source.