A variational approach to gas-liquid interface dynamics with moving contact line #

Gyula Toth, Andrew Archer, Dmitri Tseluiko, Agnes Bokanyi-Toth

11:30 Tuesday in 4Q08.

Part of the Thin films and contact lines session.

Abstract #

Onsager’s variational principle enables us to derive dynamical equations describing the time evolution of slow variables in dissipative non-equilibrium systems. On the practical level, the principle is applied either for a set of scalar or for a set of field variables, and therefore provides a set of coupled ordinary or partial differential equations, respectively. Here we present a generalisation of the framework, where the physical state of the system is described by a mixture of scalar and field variables. We will show that the “hybrid” framework naturally results in energy minimising dynamical equations obeying conservation laws for arbitrary energy and conserved quantities. To demonstrate its robustness, we will apply the theory to model the dynamics of spreading droplets on flat solid surfaces as well as the relaxation of capillary bridges in case of partial wetting.