RESULTS
Experimental runs focused on
the evolution of the liquid's
concentration field both with
and without imposed
vibrations. In the absence of
vibration, there was no
movement in the system and
the concentration field mirrors
the structure of the
temperature field. However, in
the presence of external
vibration, more sophisticated
flow patterns emerged. When
vibration-free experimental
data from the concentration
profiles were compared with
numerical predictions, the
concentration profile was linear
and in agreement with the predicted profile, which suggested that g-jitter (residual vibration)
had little effect on diffusion. However, high-frequency imposed vibrations did affect diffusion,
as seen when the concentration profile deviated from the linear profile under the influence of
relatively weak fabricated vibrations.
A closer look at the effect of g-jitter on diffusion processes after the conclusion of each
experiment revealed that during the nominal (or quasi-steady) vibration period of the ISS, g-
jitter did not affect diffusion in experiments run without imposed vibrations. These results were
duplicated when the experiments were repeated with large time lags and different
temperature gradients. Furthermore, the experimental results were in agreement with numeric
simulations. However, perturbations were evident in experiments without imposed vibrations
that ran during periods with abnormal transient movements of the ISS such as orbit correction,
docking, or undocking. SODI-IVIDIL was the first successful in-orbit experiment to characterize
the effect of onboard g-jitter. The results from IVIDIL shed light on the complex mechanisms
behind vibration-induced convection and provide useful insight on how to control fluids in
space to support future physical and life science experiments.
PUBLICATION(S)
Sechenyh V, Legros JC, Shevtsova V. Measurements Of Optical Properties In Binary And Ternary
Mixtures Containing Cyclohexane, Toluene, And Methanol. J. Chem. Engineering Data, Vol. 57
(4), pp. 1036–1043. (2012) DOI: 10.1021/je201277d.
Shevtsova V, Melnikov D, Lyubimova T, Legros JC, Gaponenko Y, Saghir Z, Sechenyh V, Mialdun
A. IVIDIL: on-board g-jitters and diffusion controlled phenomena. J. Phys.: Conf. Ser, vol. 327 ,
pp. 1-10. (2011) DOI: 10.1088/1742-6596/327/1/012031
View of the Selectable Optical Diagnostics Instrument - Influence of
Vibrations on Diffusion of Liquids investigation in the Microgravity
Science Glovebox in the Columbus module of the International Space
Station. NASA image.