The three dynamical regimes of a droplet driven by thermocapillarity

JONATAN R. MAC INTYRE; JUAN MANUEL GOMBA; CARLOS ALBERTO PERAZZO; PABLO CORREA; MATHIEU SELLIER

Christchurch

Simposio; IUTAM Symposium on Recent Advances in Moving Boundary Problems in Mechanics; 2018

IUTAM

We study the behaviour of two-dimensional droplets of partially wetting liquids driven by thermocapillary forces. A sessile droplet over a non-uniformly heated surface undergoes a shear-stress along the surface of the liquid that moves the droplet from warmer to colder regions. By means of a two-term disjoining pressure model with a single stable energy minimum, we introduce the effect of a non-zero contact angle and two different model are compared. Polar liquids are modelled using London-van der Waals molecular and ionic-electrostatics molecular interactions and, nonpolar fluids with long and short-range molecular forces. The droplet dynamics model is based on the lubrication approximation and the resulting partial differential equation is solved in the Finite Element package COMSOL Multiphysics. As a result of a parametric study on the contact angle, we characterize three different regimes of behaviour.