Experimental detection of superclusters of water droplets in homogeneous isotropic turbulence

Abstract

We present a new technique to study preferential concentration of inertial particles in (active) grid generated turbulence. This method, based on the use of a Taylor hypothesis combined to high-speed imaging, allows to reconstruct unprecedentedly long fields of particles and therefore to analyse new large-scale features, not easily resolvable with standard high-speed imaging methods. We first show that the new approach robustly reproduces results on particles clustering previously reported from standard methods. We then extend the analysis to show the first evidence of superclustering (existence of clusters of clusters) of inertial particles in turbulence and present the first characterization of superclusters.