Coupling between buoyancy and Marangoni convection in a two-fluid system under reduced gravity: A numerical study

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Conference Proceeding

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A system of two fluids having different thermo-physical properties is considered. In a rectangular domain with differently heated side walls a discrete interface exists separating both fluids. In any case a Marangoni flow is generated by temperature differences along that interface. On earth buoyancy driven flow interacts with the thermocapillary (Marangoni) flow showing a rather complicated flow pattern. This configuration roughly describes the situation in a frontal polymerization experiment where a monomer (fluid 2) is converted into a polymer (fluid 1). It does not exactly represent frontal polymerization but it is a first step toward understanding how transient and residual g can affect frontal polymerization and other reactive systems with sharp concentration gradients. If the experiment is done in space the convective influences can be reduced considerably but a new problem arises because there is no real zero gravity in a space station. A certain residual g level or transient impulses will affect the flow behavior permanently. In a numerical study it can be shown that a bifurcation problem exists for the given geometry, the set of equations and boundary conditions. Starting from the zero gravity case the transient simulations show that depending on the amplitude and duration of a small gravity pulse oscillatory modes are possible. The order of magnitude of the corresponding flow velocities can exceed the zero-gravity ones considerably. As a consequence of these results it should be well known which residual g can be tolerated in order to estimate its influence on a certain fluid flow experiment. © 2002 American Institute of Aeronautics & Astronautics.

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40th AIAA Aerospace Sciences Meeting and Exhibit

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