The onset of turbulence in particle-laden pipe flows

TL;DR

This paper introduces a scaling law linking particle-induced perturbations to the critical Reynolds number for turbulence onset in particle-laden pipe flows, based on extensive experimental data, and distinguishes different transition regimes.

Contribution

It presents a novel scaling law relating particle perturbations to turbulence onset, incorporating particle size and volume fraction, and classifies transition types in suspension flows.

Findings

Re_s,c scales as the inverse of perturbation amplitude psilon

Perturbation amplitude depends on particle-to-pipe diameter ratio and volume fraction

The law distinguishes classical, intermediate, and particle-induced transition regimes

Abstract

We propose a scaling law for the onset of turbulence in pipe flow of neutrally buoyant suspensions. This scaling law, based on a large set of experimental data, relates the amplitude of the particle-induced perturbations ($\epsilon$) to the critical suspension Reynolds number, $Re_{s,c}$. Here $\epsilon$ is a function of the particle-to-pipe diameter ratio and the volume fraction of the suspended particles, $\epsilon = (d/D)^{1/2} \phi^{1/6}$. $Re_{s,c}$ is found to scale as $\epsilon^{-1}$. Furthermore, the perturbation amplitude allows a distinction between classical, intermediate and particle-induced transition.