Dynamics of thin liquid films on a porous substrate in zero gravity

Abstract

The long-wave dynamics of liquid films on isothermal substrates show a dynamic competition between various physical mechanisms. If the destabilizing effect of thermocapillarity overcomes the stabilizing effect of surface tension and gravity, the liquid film ruptures in finite time, through the formation of primary and secondary thermocapillary finger structures. The long-wave evolution dynamics are compared for two different substrate types: isothermal non-porous and isothermal porous for small Biot number in a zero gravity environment. The multi-time-scale dynamics is revealed through time scales obtained from a method of similarity solutions. It is observed that with an isothermal porous substrate, in zero gravity, secondary thermocapillary structures are damped through imbibition and that primary thermocapillary structures persist for long times without rupture.