On the stability and prominent features of Marangoni flow in classical models of the Floating Zone technique in normal and microgravity conditions

The analysis deals with a comparative study of available experimental, theoretical and numerical results about the dynamics of hydrothermal and hydrodynamic flow instabilities in various geometrical configurations traditionally assumed as models of the Floating Zone technique. The crucial role played by the boundary conditions together with the model liquid used for the experiments is discussed in a critical and quite exhaustive way while providing a rigorous framework for a better understanding of the heterogeneous variety of results appeared in the literature over the last twenty years (often in apparent disagreement and/or providing only disjoint glimpses to the problem). The interplay among Marangoni flow and several gravity effects is considered as an additional relevant parameter contributing to the complexity of the subject. Some unpublished results are used to support the discussions.