Stability of shear layers in the interface of a binary liquid system - Experiment definition, 3-D numerical problem formulation, 2-D numerical results for steady basic flow, results of ground based preparation experiments on basic flow

The stability of interfaces or surfaces with respect to local perturbations is important for a number of technical applications in micro gravity environments, such as fuel tanks, crystal growth and other types of multi phase flow. Gravity has a stabilizing effect on disturbed surfaces. Without this stabilization the surface/interface will be destroyed if the absolutely instable regime is reached. The possibility to predict the stability of surfaces/interfaces will make applications with much larger areas of free surfaces possible. The theory of local perturbations is able to predict disturbance amplification in interfaces with temperature gradients. The stability of disturbances cannot be experimentally evaluated under the attenuating influence of gravity, since buoyancy and thermocapillar effects cannot be separated in the experiment. The purpose of the defined space experiment is to contribute to the validation of the models in micro gravitation. First results of the ground based preparation experiments are presented and compared to results of numerical simulations by a newly developed code. Experiment results are evaluated using a new 3D tomographic method for interpretation of differential interferograms.