Regular Article

Particle-depletion dynamics in axisymmetric thermocapillary flows

Vienna University of Technology, Institute of Fluid Mechanics and Heat Transfer, Getreidemarkt 9, 1060 Vienna, Austria

^a e-mail: h.kuhlmann@tuwien.ac.at

Received: 6 August 2014
Revised: 16 February 2015
Published online: 8 April 2015

Abstract

The removal of suspended particles from the interior of a thermocapillary liquid bridge via a finite-particle-size effect restricting the particle motion near the free surface is analyzed in the framework of a model flow. The particle depletion occurs on the same short time scale as does the particle accumulation in experiments. Furthermore, the time scale diverges in a similar manner for decreasing particle size. The dependence of the time scale for particle accumulation on the particle size is explained in terms of a diverging return time to the free surface for those finite-size particles which are subject to the particle-free surface-interaction.