GeoFlow: The ISS experiment and 3D numerical simulation on thermal convection in spherical shell

Abstract

Research on thermal convection in spherical shells is a fundamental model in geophysical fluid dynamics. Instabilities provide details for understanding large scale geophysical motions as convective transport phenomena in the Earth´s liquid outer core. We want to face this hydrodynamical problem within an experiment on thermal convection in rotating spherical shells influenced by a central force field. This experiment will take place at International Space Station in European Columbus Modul inside Fluid Science Laboratory (FSL). The special experiment container is called ‘GeoFlow’. Central force field is produced using effect of a dielectrophoretic force by impressing an alternating high voltage on the inner sphere. Optical measurement methods as Wollaston shearing interferometry will be used to determine the temperature fields and flow patterns. Numerical and theoretical studies of spherical Rayleigh-Bénard problem under a central dielectrophoretic force in microgravity environment are accomplished for a wide range of radius ratio, Prandtl, Rayleigh and Taylor number. For testing the FSL environment and ‘GeoFlow’ framework a laboratory experiment is designed and constructed including set-up of optical measurement techniques. In principle it has the same proportion as the original GeoFlow experiment.