Movement of drops and bubbles
Elements of fluid mechanics - Application to porous media

A fluid globule is distinguished from a rigid spherical globule by its viscosity η _g , which is not infinite, and by the continuous globule/phase interfacial tension σ.

For a spherical globule of diameter d, which is subjected neither to deformation nor oscillation, and in laminar flow (Re _g < 1), the globule's velocity is equal to the free-fall velocity given by Stokes' formula (6) , multiplied by a corrective factor, Hadamard's coefficient H :