Activities in preparation of the sounding rocket experiment on oscillatory Marangoni flow

The experiment "Pulsating and Rotating instabilities (PULSAR)", to be performed on board the Maxus 3 sounding rocket in spring 1998, is aimed at identifying the features of the oscillatory flow regime that is established in a cylindrical liquid bridge when a sufficiently large temperature difference is imposed between the supporting disks. The investigators intend to confirm previous numerical results that predict for a large Prandtl number liquid a first transition from the axi-symmetric steady to a three-dimensional oscillatory flow, characterized by temperature spots pulsating at fixed positions in the liquid column and then a second transition from the pulsating regime to another model, with temperature spots rotating in the azimuthal direction.
This paper reports on the activity in preparation of the experiment, consisting in extensive numerical simulations, complemented by laboratory experiments performed with a microscale apparatus. The results of the computations and of the microscale experiments define an experimental procedure that makes optimum use of the microgravity time available during the sounding rocket experiment.