Detailed comparative study and a mechanistic model of resuspension of spherical particles from rough and smooth surfaces

TL;DR

This study uses 3D particle tracking to compare how particles resuspend from rough versus smooth surfaces under tornado-like vortices, revealing higher resuspension efficiency from rough surfaces and proposing a mechanistic model.

Contribution

It provides the first detailed mechanistic model explaining why rough surfaces enhance particle resuspension compared to smooth surfaces.

Findings

Higher resuspension rates from rough surfaces across all tested Reynolds numbers

Particle velocities and accelerations are greater over rough surfaces

The model aids in improving predictions of resuspension in engineering and environmental contexts

Abstract

Resuspension of solid particles by a tornado-like vortex from surfaces of different roughness is studied using a three-dimensional particle tracking velocimetry (3D-PTV) method. By utilizing the three-dimensional information on particle positions, velocities and accelerations before, during and after the resuspension (lift-off) event, we demonstrate that the resuspension efficiency is significantly higher from the rough surface, and propose a mechanistic model of this peculiar effect. The results indicate that for all Reynolds numbers tested, the resuspension rate, as well as particle velocities and accelerations, are higher over the rough surface, as compared to the smooth counterpart. The results and the model can help to improve modeling and analysis of resuspension rates in engineering and environmental applications.