Three-dimensional turbulence generated homogeneously by magnetic particles

TL;DR

This paper introduces a novel method for generating three-dimensional homogeneous turbulence using magnetically driven particles, enabling experimental conditions similar to numerical simulations.

Contribution

It presents an original volumetric forcing technique with magnetic particles that produces nearly isotropic turbulence without mean flow, aligning experiments with simulation conditions.

Findings

Confirmed stationary, homogeneous, isotropic turbulence features

Estimated Tennekes' constant experimentally

Validated energy spectra and structure functions

Abstract

Three-dimensional turbulence is usually studied experimentally by using a spatially localized forcing at large scales (e.g. via rotating blades or oscillating grids), often in a deterministic way. Here, we report an original technique where the fluid is forced in volume, randomly in space and time, using small magnetic particles remotely driven. Such a forcing generates almost no mean flow and is closer to those of direct numerical simulations of isotropic homogeneous turbulence. We compute the energy spectra and structure functions using local and spatiotemporal flow velocity measurements. The energy dissipation rate is also evaluated consistently in five different ways. Our experimental results confirm the stationary, homogeneous and isotropic features of such turbulence, and in particular the Tennekes' model for which the Tennekes' constant is experimentally estimated.