Particle-Pair Relative Velocity Measurement in High-Reynolds-Number Homogeneous and Isotropic Turbulence Using 4-Frame Particle Tracking Velocimetry

TL;DR

This paper introduces a straightforward method using 4-frame particle tracking velocimetry to accurately measure particle-pair relative velocities in high-Reynolds-number turbulence, validating effects like path-history and inertial filtering.

Contribution

It presents a novel application of routine PIV hardware for precise RV measurement in isotropic turbulence, experimentally verifying key inertial effects at large separations.

Findings

Accurate RV measurement using standard PIV hardware.

Verification of path-history effects on particle pairs.

Observation of inertial filtering effects at large separations.

Abstract

The radial relative velocity between particles suspended in turbulent flow plays a critical role in droplet collision and growth. We present a simple and accurate approach to RV measurement in isotropic turbulence - planar 4-frame particle tracking velocimetry - using routine PIV hardware. This study demonstrates the feasibility of accurately measuring RV using routine hardware and verifies, for the first time, the path-history and inertial filtering effects on particle-pair RV at large particle separations experimentally.