Eur. Phys. J. E (2020) 43: 13
https://doi.org/10.1140/epje/i2020-11936-1

Regular Article

Drag force on a particle straddling a fluid interface: Influence of interfacial deformations

¹ University of Bordeaux, CNRS, Centre de Recherche Paul Pascal (UMR 5031), F-33600, Pessac, France
² University of British Columbia, Department of Mathematics, V6T 1Z2, Vancouver, BC, Canada

^* e-mail: jean-christophe.loudet@u-bordeaux.fr

Received: 22 November 2019
Accepted: 29 January 2020
Published online: 18 February 2020

Abstract

We numerically investigate the influence of interfacial deformations on the drag force exerted on a particle straddling a fluid interface. We perform finite element simulations of the two-phase flow system in a bounded two-dimensional geometry. The fluid interface is modeled with a phase-field method which is coupled to the Navier-Stokes equations to solve for the flow dynamics. The interfacial deformations are caused by the buoyant weight of the particle, which results in curved menisci. We compute drag coefficients as a function of the three-phase contact angle, the viscosity ratio of the two fluids, and the particle density. Our results show that, for some parameter values, large drag forces are not necessarily correlated with large interfacial distortions and that a lower drag may actually be achieved with non-flat interfaces rather than with unperturbed ones.