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Brief Summary

Simulation of Geophysical Fluid Flow under Microgravity (GeoFlow) is an ESA investigation planned for the Fluid Science Laboratory (FSL) on the ISS. Geoflow will study thermal convection in the gap between two concentric rotating spheres to model Earth's liquid core.

E-USOC is the responsible centre of operations' preparation, validation, and execution for GeoFlow experiment. Broadly, E-USOC monitors, commands and coordinates this Payload in Real-time operations.

Significant Dates

  • Mission STS-122: February 7th, 2008 - Columbus launch
  • Successful activation of GeoFlow: August 6th, 2008
  • First Experimental Run: August 7th, 2008
  • Latest Experimental Run: January 09-10th, 2009

Experiment/Payload Description

The Geoflow experiment is of importance in such areas as flow in the atmosphere, the oceans, and the movement of Earth’s mantle on a global scale as well as other astrophysical and geophysical problems having spherical geometry flows shaped by rotation and convection. It is also the first experiment to take place within the Fluid Science Laboratory inside the European Columbus Laboratory.

The experiment will investigate the flow of an incompressible viscous fluid (silicone oil) held between two concentric spheres. A central force field is introduced by applying a high voltage difference between the two spheres. Maintaining the inner sphere at a higher temperature to the outer sphere also creates a temperature gradient from inside to outside.


Source: EADS Astrium

This geometrical configuration can be seen as a representation of the Earth, where the role of gravity is played by he central electric field. These experiments require a weightless environment in order to “turn off” the unidirectional effect of gravity on Earth he Fluid Cell Assembly of Geoflow, the core of the experiment. The thermal convection will be observed between the two spheres, measuring the temperature distribution with the spheres revolving around a common axis at low, medium and high rotation rates and also whilst stationary. In the case of a high rotation rate high centrifugal effects are expected.

Fluid Science Laboratory with lower Central Experiment Module Open. This will be the location of the Geoflow Experiment Container.


Measurement of the temperature distribution will be carried out using Wollaston Shearing Interferometry, though additional optical diagnostics may also be used (Schlieren or hadowgraphy).

Understanding and controlling fluid flow in a spherical geometry under the influence of rotation will also be useful in a variety of engineering applications, such as improving spherical gyroscopes and bearings, and centrifugal pumps. Furthermore, study of effects, which serve to simulate the central gravity field, will find applications in areas such as high-performance heat exchangers and in the study of electroviscous phenomena. It will also help to understand the motion of liquids in several ground-based industrial applications where injected ions are a source of charge, e.g. in electrostatic precipitators and ion-drag pumps.

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