Effect of surface incompressibility on the mobility of a prolate spheroid near a liquid-gas interface
Phys. Rev. Fluids 10, 104002 – Published 10 October, 2025
DOI: https://doi.org/10.1103/lxyt-d1sm
Abstract
The resistance matrix coefficients of a rigid prolate spheroidal particle immersed in a Newtonian liquid near an incompressible, flat, and unbendable liquid-gas interface are computed by finite element simulations. The effects of the spheroid aspect ratio, the particle-interface distance, and a small inclination of the particle major axis with respect to the interface are investigated. The incompressibility condition applied to the interface reproduces a resistance matrix with translational and rotational components for movements parallel to the interface that resemble those obtained by imposing a slip boundary condition. On the contrary, the incompressible interface behaves like a no-slip rigid boundary for friction components corresponding to a particle motion orthogonal to the interface. These friction components are significantly affected by the orientation of the particle, especially for elongated spheroids at small distances from the interface. A comparison between the numerical predictions and the experimental data available in the literature is also carried out.
