The three dynamical regimes of a droplet driven by thermocapillarity

MAC INTYRE J. R.; GOMBA, J. M.; PERAZZO, CARLOS ALBERTO; CORREA, P. G.; SELLIER M,

IUTAM Bookseries

SPRINGER

Año: 2018 vol. 34

1875-3507

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 models are compared. Polar liquids are modelledusing London{van der Waals and ionic-electrostatics molecular interactions and, non-polar fluids with long- and short-range molecular forces.The droplet dynamics model is based on the lubrication approximationand 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.