The effect of flow initial conditions and geometry on the saturation of the thermo-electrohydrodynamic instability within microgravity conditions

The present study investigates the thermo-electrohydrodynamic-induced convection in a dielectric fluid confined between two concentric differentially heated cylinders under microgravity conditions through experimental means. The experiments were conducted during parabolic flight campaigns. In the present study, our primary focus was on the saturation of perturbations induced by thermo-electrohydrodynamic instability. The effect of initial flow conditions on perturbation growth rates is examined when entering the microgravity phase. Furthermore, a series of experimental setups with varied lengths and aspect ratios were considered to investigate the impact of geometry on flow behavior. The present study quantitatively investigated the flow using particle image velocimetry in the meridional and radial–azimuthal planes. Furthermore, direct measurements were taken of the global response of the flow, in this case heat transfer, using a heat flux sensor attached to the outer cylinder wall.