The geophysical fluid flow cell (GFFC) experiment simulates a wide variety of thermal convection phenomena in spherical geometry. By applying an electric field across a spherical capacitor filled with a dielectric liquid, a body force analogous to gravity is generated around the fluid. The force acts as a buoyant force in that its magnitude is proportional to the local temperature of the fluid and in the radial direction perpendicular to the spherical surface. In this manner, cooler fluid sinks toward the surface of the inner sphere while warmer fluid rises toward the outer sphere. The value of this artificial gravity is proportional to the square of the voltage applied across the sphere and can thus be imposed as desired. With practical voltages, its magnitude is only a fraction of earth's and so requires a microgravity environment to be significant. The advantage of using this apparatus is that it simulates atmospheric flows around stars and planets, i.e. the "artificial gravity" is directed toward the center of the sphere much like a self-gravitating body.
The GFFC experiment flew on Spacelab 3 in April/May and operated for more than 100 hours during the mission. The experiment verified that dielectric forces can be used to properly simulate a spherical gravitational field to drive thermal convection. By controlling the relative importance of thermally driven buoyancy an entire spectrum of convective motion was observed, from the initial onset of laminar convection to fully turbulent flow.
The GFFC is scheduled to fly again on STS-73, the United States Microgravity Laboratory, mission 2 (USML-2). The experiments planned for USML-2 are:
The GFFC science team consists of :
Dr. Leslie will also be conducting the experiments aboard Columbia during the mission as a payload specialist. For more information about USML-2.
Responsible Official: Dr. James E. Arnold (jim.arnold@msfc.nasa.gov)
Page Curator: Paul J. Meyer (paul.meyer@msfc.nasa.gov)