  To date, the influence of non-linear stratifications and two layer
stratifications on internal wave propagation has been studied for
two-dimensional wave fields in a cartesian geometry. Here, we use a novel wave
generator configuration to investigate transmission in non-linear
stratifications of axisymmetric internal wave. Two configurations are studied,
both theoretically and experimentally. In the case of a free incident wave, a
transmission maximum is found in the vicinity of evanescent frequencies. In the
case of a confined incident wave, resonant effects lead to enhanced
transmission rates from an upper layer to layer below. We consider the
oceanographic relevance of these results by applying them to an example oceanic
stratification, finding that there can be real-world implications.

Fluid Dynamics