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

J.-C. Loudet, M. Qiu, J. Hemauer and J. J. Feng

Eur. Phys. J. E 43, 13 (2020).

Abstract - We numerically investigate the influence of interfacial deformations on the drag force exerted on an isolated 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 whereas the flow dynamics is solved in the limit of small Reynolds and capillary numbers. 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 lower drag may actually be achieved with non-flat interfaces than with unperturbed ones. We compare our results with a few relevant experimental results prior to considering further extensions of our study.