Validation of Numerical Simulation of Drop Motion on Surfaces With Micro Patterns

Numerical simulation of drop motion on surfaces with micro patterns is conducted. The results are compared with existing experimental and analytical studies to validate the reliability of the numerical simulations. In the comparison of the liquid phase morphology on a surface with straight grooves, it is confirmed that a variety of liquid shapes, including droplets, filaments with positive/negative Laplace pressure and so on are successfully reproduced by the numerical simulation. Moreover, the numerically observed transition between these morphologies in a broad range of the groove aspect ratio and the static contact angle agrees with the morphology diagram which is obtained by a semi-analytic approach based on the surface free energy minimization. Furthermore, in the comparison of the spreading behaviors of a liquid drop on a surface with square pillars, it is shown that the numerical simulations can predict the time-dependent drop deformation during the spreading process. The comparison of the length of two spreading modes shows a quantitative agreement with the experimental results.