Convection induced by a fluctuating acceleration field

Cavity flow induced by a fluctuating gravitational field normal to an initially imposed density gradient is considered. This configuration is a simplified model to study fluid flow in a directional solidification cell subjected to external accelerations, such as those encountered in a typical microgravity environment. The effect of both periodic deterministic disturbances and narrow band noise are considered. It is found in the latter case that the mean squared displacement of a fluid element grows as a power law in time, and that the particular exponent depends on whether viscous effects are important.