SIMULTANEOUS OBSERVATION OF ENERGY AND ENSTROPHY CASCADES IN THIN-LAYER TURBULENCE

Hua Xia,Nicolas Francois,Horst Punzmann,David Byrne,Michael Shats

doi:10.1142/s201019451660185x

Hua Xia, Nicolas Francois + Show 3 more

Open Access

https://doi.org/10.1142/s201019451660185x

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Abstract

We report the simultaneous observation of the inverse energy and direct enstrophy cascade in thin-layer turbulence. The experiments are conducted in an electromagnetically driven flow with layers of stratified fluid. Recent questions regarding the two-dimensionality of electromagnetically driven turbulence in such experiments are addressed.

Highlights

Driven turbulence in thin layers of fluids has been the focus of intense research for the past two decades
The purpose of this paper is to address the question of the two-dimensionality of thinfluid-layer experiments and discuss the conditions in which they can be treated as twodimensional. The first such experiments[3] were conducted with a layer of mercury on a solid substrate. This initial experiment supported the prediction by Kraichnan of the inverse energy cascade with the observation of k-5/3 for half a decade of wave numbers below the energy injection scale
Later, using a different magnet array[8], it is reported, for the first time in thin layers, energy spectra that was consistent with the enstrophy cascade k-3 over a full decade of wave numbers

Summary

Introduction

Driven turbulence in thin layers of fluids has been the focus of intense research for the past two decades. The purpose of this paper is to address the question of the two-dimensionality of thinfluid-layer experiments and discuss the conditions in which they can be treated as twodimensional. This initial experiment supported the prediction by Kraichnan of the inverse energy cascade with the observation of k-5/3 for half a decade of wave numbers below the energy injection scale.

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