STATISTICAL SATURATION OF BUOYANT FLOW-INDUCED BY A FLUCTUATING ACCELERATION

We study buoyancy-driven convection in a laterally heated, two-dimensi onal cavity under a fluctuating acceleration field, to model flow cond itions in a microgravity environment. In the limit of a large aspect r atio cavity (the length in the direction perpendicular to the temperat ure gradient is much larger than in tile parallel direction), an analy tic solution can be found in which the flow reaches a statistical stea dy state of zero average vorticity and mean squared vorticity that sca les as the stochastic Rayleigh number squared. We also present the res ults of a full numerical solution of the Navier-Stokes equation for a fluid driven by a fluctuating acceleration field in a square cavity an d confirm the scaling of the flow obtained in the asymptotic analysis.