Development of measurement method for investigating three dimensional turbulence structures in liquid-slid flow

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The aim of this study is to develop a measurement technique for understanding three dimensional turbulence structures in liquid-solid flows. This study is composed of two processes ; one is for improvement of Super Resolution PIV developed by Takehara on time resolution and the other is for improvement of 3-D stereo PIV developed by Watanabe on space resolution.Although the super resolution PIV can measure the flow field with high space resolution by using many particle tracers for visualization, it did not have enough time resolution because we did not have enough capturing system. This problem was overcome by purchasing a high-speed video system with high resolution and wide range with great help of this scientific research fund. By using this high-speed video system the images of flow fields inside and in the vicinity of a porous body were captured. And generation and decay mechanisms of turbulence flow inside the porous body and in the downstream region have been studied in detail. … More Although the 3-D stereo PIV can measure the three dimensional flow structures, it needed a great investment of time to analyze if many particle tracers were seeded in fluid. This problem was overcome by improving calculation algorism. As a result the 3-D stereo PIV was reconstructed as a PIV system with high space resolution. The improved 3-Dstereo PIV was applied to a multi-phase flow under the breaking zone. It has been found that the improved 3-D stereo PIV is a useful tool for measurement of complex fluid flow and sediment motion under breaking waves.Furthermore, a new image velocimetry, called "path line connecting velocimetry", has been developed for measurement of the liquid-solid flows with high speed fluid motion and strong turbulence with three dimensional structure. The "path line connecting velocimetry" has been applied to the measurement of the flow field induced by particle motion. As a result, it was shown that the path line connecting velocimetry is a very useful tool for measurement of multi-phase flows including particles with high concentration and water surface. Less