Effect of the Initial Conditions on the Growth of Thermoelectric Instabilities During Parabolic Flights

The dielectrophoretic force is applied between two differentially heated cylinders under microgravity conditions obtained during parabolic flight. The electric field is activated at various moments of the microgravity phase in order to control the initial condition at which the dielectrophoretic force intervenes. The time evolution of the flow is measured by particle image velocimetry and that of thermal plumes is captured by shadowgraphy. The growth rate of the instability during microgravity conditions is determined from these measurements. It is found that the closer the initial condition to the purely conductive state is, the faster the instability grows.