Simulation of Geophysical Fluid Flow under Microgravity-I (Geoflow-I)
Research Area: Fluid Physics
Expedition(s): 16 and 17
Principal Investigator(s): ● Christoph Egbers, PhD, Brandenburg University of
Technology, Cottbus, Germany
RESEARCH OBJECTIVES
Physical mechanisms of heat driven rotating fluids are important
for a large number of geophysical problems such as explaining the
convection of the Earth’s liquid outer core. The main objective of
the Geoflow investigation is to study the stability, pattern
formation, and transition to chaos of thermal convection in fluid-
filled rotating spheres. Understanding how Earth’s mantle flows
is a major interest for geophysics because it could help to
explain earthquakes or volcanic eruptions. The results, for
example, could also benefit by improving spherical gyroscopes,
bearings, and centrifugal pumps.
RESULTS
In geophysical and astrophysical research, the setup of rapid
rotating spherical shell convection, as part of dynamic flow, is of
basic interest. Data analysis identifies first subcritical and
supercritical fluid flow patterns. In addition, the fully developed
supercritical states turn out to have buoyancy-driven polar
exchange and complex drift behavior. If these convective flow
patterns can be reconstructed, numerical simulations could
show details on other properties of the fluid flow beyond the
limits of what is available with in-orbit measurement
techniques. Quality of the images is excellent and classifying of
patterns into space and time is possible. Overall analysis will be
done when the set of experiments is completed, including the
ongoing GeoFlow II.
PUBLICATION(S)
Futterer B, Egbers C, Dahley N, Koch S, Jehring L. First identification of sub- and supercritical
convection patterns from ‘GeoFlow,’ the geophysical flow simulation experiment integrated in
Fluid Science Laboratory. Acta Astronautica. 2010;66(1-2):193-200. doi:
10.1016/j.actaastro.2009.05.027.
Jehring L, Egbers C, Beltrame P, et al. Geoflow: First results from geophysical motivated
experiments inside the fluid science laboratory of Columbus. 47th Aerospace Sciences Meeting and
Exhibit, Orlando, FL; 2009.
This investigation is complete and all results are published.
Geoflow-I: Experimental fringe
pattern images projected on a
spherical surface indicating
column-like thermal flow (top)
and agreement with numerical
simulated flow field (bottom).
ESA image.