Thermocapillary Bubble Migration at Higher Marangoni numbers - Theory and Experiment

Single bubble motion driven purely by thermocapillarity (i.e. a linear temperature gradient in the surrounding liquid) is analyzed theoretically with the following steps: A full numerical simulation up to Re of several hundreds depending on the Prandtl-number of the liquid, and a simple analytical treatment describing the asymptotic migration at high Re. Results of short-term microgravity experiments performed at drop Tower Bremen will be reported for 20 < Re < 160. The theoretical migration velocities are slightly higher than the experimental values which might be due to the short-time nature of the experiments. An unsteady theoretical analysis will be given explaining, at least in part, the remaining discrep-ancy between theory and experiment.