Laboratory and numerical studies of internal gravity wave propagation in a sheared environment

A series of laboratory experiments and numerical simulations of the propagation of an internal gravity wave in a sheared environment have been conducted, illustrating several effects of shear on wave propagation and facilitating an assessment of the usefulness of linear theory and the role of nonlinearity in wave/shear interaction. Both experimental and numerical results exhibit vertical scale compression, perturbation velocity and shear enhancement, the formation and breakdown of unstable layers, viscous damping, and critical-level attenuation of an incident wave packet. The linear numerical results are noted to be in quantitative agreement with the experimentally observed flows up until the formation of unstable layers, for the cases of both critical and supercritical phase velocities.