Simultaneous 2D and 3D turbulent flows in Faraday Waves

TL;DR

This study provides the first experimental evidence of simultaneous 2D and 3D turbulence in Faraday wave-driven flows, revealing complex energy cascades and interactions between surface and bulk turbulence.

Contribution

It demonstrates the coexistence of 2D and 3D turbulence in a single flow driven by Faraday waves, with detailed velocity field analysis.

Findings

Inverse energy cascade at the surface

Direct energy cascade in the bulk

Surface turbulence drives bulk flow via vertical jets

Abstract

In nature turbulent flows exist that are neither simply 2D nor 3D but boundary conditions, such as varying stratification, force them towards the one or the other. Here, we report the first evidence of the co-existence of 2D and 3D turbulence in an experimental flow driven by Faraday waves in water. We find that an inverse energy cascade at the fluid surface and a direct energy cascade in the 3D bulk flow underneath exist simultaneously. We base our analysis on temporally and spatially well-resolved velocity fields measured at horizontal and vertical planes. The findings suggest that the strongly turbulent 2D surface flow drives the 3D bulk flow through sporadic vertical jets as a source of momentum.