Inverse energy cascade and emergence of large coherent vortices in turbulence driven by Faraday waves

TL;DR

This study demonstrates the formation of large coherent vortices through inverse energy cascade in Faraday wave-driven turbulence, revealing two-dimensional turbulence-like behavior in a three-dimensional system.

Contribution

It provides experimental evidence of inverse energy cascade and vortex formation in Faraday wave turbulence, expanding understanding of wave-driven turbulent flows.

Findings

Large coherent vortices form via inverse energy cascade.

Horizontal velocity fluctuations resemble 2D turbulence.

Inverse cascade confirmed by spectral and statistical analysis.

Abstract

We report the generation of large coherent vortices via inverse energy cascade in Faraday wave driven turbulence. The motion of floaters in the Faraday waves is three dimensional but its horizontal velocity fluctuations show unexpected similarity with two-dimensional turbulence. The inverse cascade is detected by measuring frequency spectra of the Lagrangian velocity, and it is confirmed by computing the third moment of the horizontal velocity fluctuations. This is observed in deep water in a broad range of wavelengths. The results broaden the scope of recent findings on Faraday waves in thin layers [A. von Kameke, \textit{et al.}, \textit{Phys. Rev. Lett.} \textbf{107}, 074502 (2011)].