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

本研究的初衷是利用彩色图像信息，提高流速测量的精度，同时利用云纹法得到势场，用示踪法得到速度矢量场。然而，对于后一种目的，事实证明，同时测量上述两个量的可视化方法在技术上是困难的。因此，我们将注意力集中在一种温度和流场共存的自由对流上。用液晶示踪剂对这两个场进行了可视化。根据可视化的彩色图像，完成了速度矢量和温度分布的同时测量。在此基础上，开发了三维流场速度矢量分布图像处理仪器系统，具体验证了以下研究结果。1)建立了相关法速度矢量分布图像处理仪器系统。实践证明，即使是在非定常流场中，该系统也是非常有用的。并给出了错误速度矢量的校正算法。2)通过对图像进行彩色分离，得到了三维水流不同水深的速度矢量分布。然而，在该彩色图像处理仪器系统中，颜色测量的空间分辨率仍然较低。因此，未来需要解决的问题是开发一种广泛应用的分色算法，研究温度与颜色之间的严格关系。

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.