Fluid flow induced by a random acceleration field

We use a stochastic model of the residual acceleration field onboard spacecraft (g-jitter), and study the fluid motion that is induced in three different configurations. These configurations have been chosen because they illustrate behavior that is peculiar to a stochastic acceleration, and to emphasize differences with other treatments that are based on a deterministic, and often periodic, acceleration field. In the first case, we show that g-jitter can induce effective attractive or repulsive forces between two spherical particles that are suspended in an incompressible fluid of different density. Second, we show that resonance between a stochastic modulation of the control parameter appropriate for a pitchfork or supercritical bifurcation and linearly stable modes can lead to a shift in the threshold for instability. Finally, we discuss the classical problem of vorticity diffusion away from a plane boundary that is being vibrated along its own plane. Periodic motion with zero average vorticity production results in an exponential decay of the vorticity away from the boundary. Random vibration, on the other hand, results in power law decay away from the boundary even if vorticity production averages to zero.