Estimates on diagnostic methods for investigations of thermal convection between spherical shells in space

Thermal convection in a spherical shell represents an important model in fl uid dynamics and geophysics. Investigations on thermal convective instabili ties occurring in the spherical gap flow under terrestrial conditions are o f basic importance, especially for the understanding of symmetry-breaking b ifurcations during the transition to chaos, Microgravity experiments on the rmal convection with a simulated central force field are important for the understanding of large-scale geophysical motions such as the convective tra nsport phenomena in the Earths liquid outer core. More than one diagnostic tool is needed to examine and characterize the different flow types. Flow v isualization, Wollaston shearing interferometry and laser Doppler velocimet ry should be available for space experiments. This report summarizes concur rent theoretical, numerical and experimental studies for the preparation of a Get Away Special (Shuttle) experiment as well as a Space Station experim ent inside the Fluid Science Laboratory. The special experimental device fo r investigations of supercritical and turbulent thermal convection in spher ical shells under a central force field with respect to geophysical simulat ions is called an electrohydrodynamic container. A central symmetric force field similar to the gravity field acting on planets can be produced using the effect of the dielectrophoretic force held by applying a high-voltage p otential difference to the inner and outer sphere.