Measurements of inertial wave packets propagating within steady rotating turbulence

The Racah Institute of Physics, The Hebrew University of Jerusalem - Jerusalem, Israel

Received: 23 July 2018
Accepted: 17 January 2019

Abstract

We measure and quantify the spatial transport of energy within steady rotating hydrodynamic turbulence. A steady turbulent field in a rotating tank is perturbed by a short and abrupt increase of energy injection at a well-defined plane. Initially, a wave packet of inertial modes is generated within the background turbulent field, propagating according to the dispersion relation of inertial waves, much like wave propagation within a static fluid. At this stage, the background turbulence is only weakly affected by the pulse passage. Only at longer times, which are determined by the pulse initial amplitude and spectrum, energy is efficiently transferred from the wave packet to the background flow. The energy, which is physically injected at the bottom of the tank, is, therefore, effectively injected at a higher plane. The height of maximum energy transfer efficiency is estimated and varied via manipulations of experimental parameters.