The feedback effect caused by bed load on a turbulent liquid flow

TL;DR

This study investigates how a mobile granular bed influences turbulent liquid flow, providing experimental data on feedback effects crucial for predicting bed-load transport and pressure drops in granular conveyance systems.

Contribution

It offers the first detailed experimental quantification of the feedback effect of a mobile granular bed on turbulent water flow using Particle Image Velocimetry.

Findings

Quantified the feedback effect of bed load on velocity profiles.

Measured pressure drops associated with mobile granular beds.

Provided data for improving bed-load transport models.

Abstract

Experiments on the effects due solely to a mobile granular layer on a liquid flow are presented (feedback effect). Nonintrusive measurements were performed in a closed conduit channel of rectangular cross section where grains were transported as bed load by a turbulent water flow. The water velocity profiles were measured over fixed and mobile granular beds of same granulometry by Particle Image Velocimetry. The spatial resolution of the measurements allowed the experimental quantification of the feedback effect. The present findings are of importance for predicting the bed-load transport rate and the pressure drop in activities related to the conveyance of grains.