Hydrodynamic drag force on a sphere approaching a liquid-liquid interface.

The difficulties involved in trying to model the motion of a solid particle through surfaces, particularly at the liquid-liquid interface, are mainly due to the continuous deformation of the surface, not only as the particle progresses through the surface, but also before its penetration into the lower liquid. This study investigated experimentally and theoretically, the hydrodynamic drag force on a sphere approaching a liquid-liquid interface. The experiment ball material of steel of different ball diameters ranging from 1.