Experimental observation of a strong mean flow induced by internal gravity waves

TL;DR

This paper reports the experimental detection of a significant horizontal mean flow generated by internal gravity waves in a stratified fluid, supported by a physical model that matches observed growth and structure.

Contribution

It provides the first experimental evidence of a strong mean flow induced by internal gravity waves and introduces a simple model explaining its growth and spatial features.

Findings

Strong horizontal mean flow observed experimentally

Good agreement between model predictions and measurements

Identification of a physical mechanism driving the mean flow

Abstract

We report the experimental observation of a robust horizontal mean flow induced by internal gravity waves. A wave beam is forced at the lateral boundary of a tank filled with a linearly stratified fluid initially at rest. After a transient regime, a strong jet appears in the wave beam, with horizontal recirculations outside the wave beam. We present a simple physical mechanism predicting the growth rate of the mean flow and its initial spatial structure. We find good agreement with experimental results.