Modeling of Drops Spreading on Random Surfaces

J. Frassy1, C. Lecot2, M. Murariu3, C. Delattre1, and A. Soucemarianadin1
1Université Joseph Fourier, Grenoble, France
2Université de Savoie, Le Bourget-du-Lac, France
3LETI, CEA, Grenoble, France

We present simulations of drops spreading on random surfaces with either chemical or topographical heterogeneities. All the computations are made within the framework of the lubrication approximation.

The droplet height is the solution of a time-dependent nonlinear fourth order partial differential equation, which is solved using COMSOL.

Fast Fourier Transform (FFT) together with an appropriate auto-correlation function helps to generate a data set, where for each surface, different coordinate heights (topographical heterogeneity) and/or different wetting angles (chemical heterogeneity) may be generated.

We demonstrate that the density and amplitude of heterogeneities have a strong influence on the spreading of the drop.