Gradient-driven fluctuations experiment: fluid fluctuations in microgravity.
We describe an experimental breadboard developed for the investigation of nonequilibrium fluctuations induced by macroscopic temperature and concentration gradients under microgravity conditions. Under these conditions the amplitude of the fluctuations diverges strongly for long wavelengths. The setup was developed at the University of Milan and at the University of California at Santa Barbara within the gradient-driven fluctuations experiment (GRADFLEX) project of the European Space Agency, in collaboration with the National Aeronautics and Space Administration. The apparatus uses a quantitative shadowgraph technique for characterization of the static power spectrum of the fluctuations S(q) and the measurement of their dynamics. We present preliminary experimental results for S(q) obtained in the presence of gravity for gradient-driven fluctuations for two cases, those induced in a liquid mixture with a concentration gradient produced by the Soret effect and those induced in a single-component fluid by a temperature gradient.
Vailati
Alberto
A
CNR-Istituto Nationale per la Fisica della Materia and Dipartimento di Fisica, Università degli Studi di Milano, Italy. vailati@fisica.unimi.it
Cerbino
Roberto
R
Mazzoni
Stefano
S
Giglio
Marzio
M
Nikolaenko
Gennady
G
Takacs
Christopher J
CJ
Cannell
David S
DS
Meyer
William V
WV
Smart
Anthony E
AE