Scattering of internal gravity waves from rough topography

Internal gravity waves incident at rough topography may be ‘scattered ’ in wavenumber and physical space. Components of the scattered wavefield may also have different amplitudes to those associated with the incident wave. Such properties are of interest in oceanic studies that seek to establish wave breaking and subsequent mixing patterns near benthic topography. This research aims to determine the scattering behaviour of internal gravity wave energy flux at boundaries containing topographic features of length scales that are comparable with the incident wavelength. An experimental investigation uses a ‘synthetic schlieren ’ technique to observe scattering of internal gravity waves in a stable linear salt-water stratification. Waves are produced by small amplitude vertical oscillation of circular cylinders. The structure of the wave beams generated are compared before and after incidence on various topography. 1