Three-dimensionality of the triadic resonance instability of a plane inertial wave

Abstract

In rotating flows dominated by inertial waves, triadic resonant interactions, and among them the triadic resonance instability, are the elementary bricks of the energy transfers between spatial scales. We demonstrate theoretically and experimentally that the triadic resonance instability of a plane inertial wave is a three-dimensional process, very efficient at redistributing the energy in the plane normal to rotation. A remarkable consequence of this result is that a turbulent sea of weakly nonlinear inertial waves will have a strong tendency to reach statistical axisymmetry.

Topics & Concepts