Real Time Instrumentation of Unsteady Flow Phenomena based upon Color Image Information

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The original purposes of this study were to improve the accuracy of flow velocity measurement and to obtain a potential field by Moire method and a velocity vector field by a tracer method at the same time by using color image information. On the latter purpose, however, it was turned out that the visualization method for measuring the above two quantities at the same time was technically difficult on investigation. Therefore, we directed our attention to a free convection in which the temperature and flow fields coexist. The two fields were visualized by using the liquid crystal tracer. From the visualized color images, simultaneous measurements of the velocity vector and temperature distributions were completed. Furthermore, the image processing instrumentation system of velocity vector distributions in three dimensional flow fields was developed.Consequently, the following results were specifically confirmed. 1) The image processing instrumentation system of velocity vector distributions by using correlation method was established. It was proved that this system was very useful for even an unsteady flow field. And, the algorism for correcting erroneous velocity vectors was developed.2) The velocity vector distributions in different water depths of a three dimensional flow were simultaneously obtained by the color separation of the image.3) The changes of temperature and velocity vector distributions with time were obtained by applying the system to the dynamic behavior of a thermal stratification. In this color image processing instrumentation system, however, the spatial resolution of color measurement is still lower. Therefore, the problem remains that to be solved in the future is to develop an extensively used color separation algorism and study the strict relation between the temperature and the color.