INFLUENCE OF VARIATIONS IN THE ANGULAR ROTATIONAL VELOCITY OF A SPACECRAFT ON THERMAL-CONVECTION UNDER CONDITIONS OF WEIGHTLESSNESS

Unlike the conventional approach where it is assumed that liquid motio n under conditions of weightlessness is caused by vibrations or residu al quasisteady-state microaccelerations, the present paper examines co nvection caused by variations in the angular rotational velocity of a spacecraft. It is shown that although the level of microaccelerations caused by variations in the angular rotational velocity is extremely l ow for the Shuttle spacecraft, Mir space station, and unmanned spacecr aft, of the order of 0.1-1 mu g, the ensuing convection and nonuniform ity in the impurity distribution during crystal growth may be very app reciable. (C) 1997 American Institute of Physics.