An efficient and highly scalable solver for modelling thin film flows in heterogeneous environments

We present an open-source, modular and highly scalable thin-film flow solver that can perform complex simulations of wetting and dewetting phenomena in the presence of substrate or environmental heterogeneities. The implementation is based on the thin-film approximation and circumvents the stress singularity at moving contact lines by assuming the presence of an ultra thin precursor film covering the whole surface. The solver is implemented within the open-source Basilisk library (http://basilisk.fr/), and is validated by comparing with the predictions of reduced-order models derived from matched asymptotics analyses for a number of representative cases with isolated droplets. The capabilities of the solver are demonstrated by simulating multiple interacting droplets sliding on an inclined and chemically heterogeneous substrate.