Internal Waves and Boundary Layers in a Density-stratified Fluid

Internal tides, generated in the density-stratified ocean by the oscillation of the barotropic tide over bottom topography, play a crucial role in the energy balance of the Earth–Moon system [1]. This has led to a recent revival of the classical topic of internal gravity wave generation by oscillating bodies. Wave energy dissipates owing to wave breaking and suband superharmonic excitation, at regions where the wave rays either intersect each other, reflect at the bottom or are tangent to the topography [2]. Accordingly, accurate modelling of the bottom boundary condition is determinant. However, all analytical models to date consider idealized free-slip boundaries instead of the actual no-slip boundaries, except for a recent study of the oscillating circular disk [3]. We specialize to this problem, review the possible theoretical approaches and compare their outcome with existing experimental data and with a new and improved set of data.