Compatibility of the microgravity environment of the international space station with fluid and material science experimentation

This paper deals with the effects of space non uniform (pendular) accelerations on fluid and material science experiments onboard the International Space Station. These motions, that can be generated by rigid body oscillations around the centre of mass of the ISS, or by elastic deformations of the structure, imply different effects on liquid behaviour onboard ISS (in particular, they generate convective motions even in isodense fluids). A very simple model of a cantilever beam is presented that shows the different roles played by linear and rotational accelerations in inducing fluid motion inside a uniform density liquid cell. Experimental data are presented for the low frequency and the high frequency (streaming) case, correlated by numerical results. Low frequency pendular motion of the Russian FOTON capsule is considered and its effects on fluid physics experimental results obtained in previous missions is analysed. The possibility of mean flow (streaming) due to high generation high frequency non-translational vibrations in a isodense fluid is considered, and comparisons are presented between on-ground experimental and numerical results. (C) 2002 Published by Elsevier Science Ltd.