PARTICLE MOTION IN THE FLUID EXPERIMENT SYSTEM IN MICROGRAVITY

Polystyrene spherical particles were used to trace the fluid motion in an experiment of crystal growth from aqueous solutions in space. This paper presents the particle motion derived from the images reconstruc ted from holograms taken in the space experiment. The particle mechani cs is also discussed. It was observed that some particles can independ ently move in different directions; some particles can move much faste r than the others, and some small particles may have the same speed as large ones. Particles may individually have the behavior of the inert ial random walk. But more importantly, there are non-random motion so that particles may keep moving in certain directions. It becomes diffi cult to estimate g and g-jitter from these particle motions as expecte d. This also leads to a doubt that the particles in the fluid experime nt system are subjected to g and g-jitter, which have been considered as only a function of time.