Inertial waves excited by topography

We bring together two important features of planetary cores: 1) wave propagation in the fluid and 2) topography of the fluid-solid interface. On one hand, inertial waves contribute to the maintenance of quasi geostrophic motions or to the formation of elongated structures in rotating turbulence. On the other hand, topography of the core-mantle boundary has been prososed in various seismological and geodynamical studies and can modify the fluid flow in the core, for example, by altering global fluid modes. Here, we focus on inertial waves excited by topography.

We present results from a combined numerical and experimental investigation of inertial wave motion which is forced by an oscillating topography. To allow comparison with the theory of linear inertial waves, we use a complex topography characterised by a single wavenumber in the spectral domain. Both, the wavenumber and the frequency of the oscillations are varied, allowing us to characterise the transport of kinetic energy at different length scales as well as the interactions of direct and reflected inertial waves.