The study of weak oscillatory flows in space experiments

Abstract

The effects of residual accelerations have been studied by using three-dimensional modeling of the flow in a rectangular cell filled with a liquid, Pr=20, the walls of which were kept at different temperatures. The system was subjected to an acceleration field, which can be decomposed into two parts: a steady component and another one which varies slowly with time, the frequency is about f₀≈10⁻³ Hz. The convective heat transport and flow characteristics are discussed for different parameters of g-jitter. The high and low frequency modulation of a sinusoidal g-jitter is discussed. To capture many of the essential characteristics of buoyancy-induced convection a new approach is suggested, which was developed based on the observation of the trajectories of tracer particles. On the one hand, it is a typical way to record the flow in experiments. On the other hand, creating database of different types of trajectories gives the possibility to solve the inverse problem. The shape of the trajectory depends on the g-jitter parameters. It is shown that for slow convective motions the tracer particles perform loops along trajectory due to g-jitter with low frequencies, and the additional high frequencies only cause trembling of the shape of these loops. Taking the experimentally recorded trajectories of tracer particles and comparing with those in the database, one can draw a conclusion about the amplitude and direction of the resulting gravity vector during the experiment.