Viscous force exerted on a foam at a solid boundary : influence of the liquid fraction and of the bubble size

TL;DR

This study experimentally investigates how liquid fraction and bubble size affect the viscous force on a foam at a solid boundary, providing a theoretical model that aligns with experimental data.

Contribution

It introduces a theoretical model linking foam properties to viscous force, validated by experimental measurements of pressure drop and flow velocity.

Findings

Force/velocity relation follows a specific power law.

Liquid fraction and bubble size significantly influence viscous force.

Model offers a new interpretation of previous experimental results.

Abstract

We study experimentally the pressure drop needed to push a bubble train in a millimetric channel, as a function of the velocity. For dry liquid foams, the influence of the amount of liquid and of the bubble size is pointed out and we predict theoretically that this influence is closely related to the power law obtained for the force/velocity relation. This model is in fair agreement with our experimental data and provides a new interpretation of previous results.