Numerical and experimental analysis of short-scale Marangoni convection on heated structured surfaces

Short-scale Marangoni flow in a film on an evenly heated horizontal wall with a structured surface is studied experimentally and numerically. The occurring two-dimensional convective rolls are fully visualized in the experiment for the first time, where a closed experimental environment allows to monitor the temperature and Biot number. For the numerical simulations, the full Navier–Stokes equations and energy equation are solved in a Volume of Fluid framework. The energy equation is solved with a novel two-field approach, which prevents numerical diffusion at the interface. The numerical results are in very good agreement with the experimentally obtained data. Simulations were performed to study the influence of film height, wall temperature, topography changes and the effect of gravity on the flow characteristics like interface velocity, flow patterns and heat transport. It is found that the interface velocity and convective heat transport both increase with increasing film height and wall temperature. Additionally a change in the flow pattern is found. Gravitational effects play a minor role and have no effect on the steady state.