The purpose of this study is to develop the experimental technology to analyze the effect of residual acceleration on the dynamics of fluid, specially on the thermal convection under microgravity conditions. A compact color Schlieren optical device combined with dye injection unit was developed for the visualization of the flow field and temperature distribution. This apparatus was applied to the gravity modulational experiments using the parabolic flight of MU-300 airplane, and the drastic changes of the flow pattern were observed accompanied with the gravity modulation and they were compared with the results of numerical simulations. It was concluded from these experiments that the color Schlieren optical device was extremely effective to investigate the distribution of both ther­mal and flow field under microgravity.

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This report describes a preliminary fluid-dynamic experiment performed in a microgravity environment during a parabolic free-falling flight of an aircraft. The flow field is a liquid bridge of silicone oil suspended between two coaxial circular disks. This particular flow geometry is to simulate that of the floating zone method, which is considered as a promising method for manufacturing large-scale semiconductor crystals in microgravity environments. In this report, an emphasis is placed on the description of the development and verification of a three-dimensional flow measurement technique which is based on the particle tracking velocimetry. An automated in-situ camera calibration method is proposed with a view to application to the future experiment planned in a space station. The measurement accuracy is checked by the actual three-dimensional measurement of the moving target marks. Some results of the fluid flow in a suspended liquid bridge are presented to demonstrate the applicability of the proposed technique to the microgravity fluid-dynamic experiments.

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