Thermal convection in an enclosure due to vibrations aboard spacecraft

摘要: This paper discusses thermal convection in an enclosure induced by spacecraft vibrations (#-jitter). Under normal circumstances (no maneuvers, no intentional spinning of the spacecraft) ^-jitter generates predominantly oscillatory velocity and temperature fields with zero time-mean values. The can also generate secondary flows nonzero mean, but they are much smaller order. Some implications g- jitter on materials processing space discussed. NE primary advantages foreseen for is reduction natural associated Earth's gravity. However, there have been some indications (e.g., Apollo 14 experiments 1'2) that might cause appreciable con- vection. Such may be important fluids ex- periments affect quality crystals grown space. Therefore, to study effectiveness generating fluid flows, present work theoretically investigates a case which fluid-filled tainer differentially heated walls subjected vibrations. Implications results In attempt evaluate effects g-jitter motions Spradley el al. 3 made numerical analysis various configurations. They considered three profiles, sinusoidal, absolute sinusoidal saw tooth, compared flowfields constant g level. found if decomposed into time mean part part, more than determining flowfield heat- transfer rate. A somewhat related has done Forbes4 where effect convective heat rectangular studied experimentally as well numerically under 1-g conditions. indicate very little when flow laminar. comprehensive et al.,3 meant give better physical insight material presented herein taken from Prasad Ostrach.5 Formulation Problem g-Jitter Consider experimental setup spaceship orbiting Earth (Fig. 1). coordinates (X0,Y0,Z0) fixed at center origin 0 (fixed frame reference), (X'f Y',Z') attached 0' its mass. coor-