Liquid film instability of an internally coated horizontal tube

A liquid film coating the inner side of a horizontal tube is prone to the Rayleigh-Plateau instability resulting from surface tension forces. However, when these capillary forces are dominated by gravity forces (i.e. when the Bond number increases), the liquid film possibly stabilizes. In this study, we determine numerically the instability threshold in good agreement with preexisting experiments and show that deformation of the interface during liquid drainage is responsible for flow stabilization.