Stability of a liquid layer draining around a horizontal cylinder: Interplay of capillary and gravity forces

We study the drainage of a viscous liquid layer on a horizontal cylinder under gravity, focusing on cases where viscous effects dominate inertia. Nonlinear simulations distinguish, as a function of film thickness and Bond number, two regimes where the draining liquid either ruptures or forms a quasistatic curtain. The liquid curtain subsequently destabilizes due to capillary and gravity forces. When surface tension dominates gravity, pearls form around the cylinder, whereas when gravity dominates surface tension, hanging droplets form, as confirmed by a linear stability analysis of the curtain.