| Summary: | 碩士 === 國立中央大學 === 機械工程研究所 === 99 === The aim of this work is to examine the dynamic behavior of granular flows with granular hydraulic-jumps. The jump is produced by using a fixed semi-circular cylinder obstacle in a rectangular sliding chute. Three different inclined angles combining with three different sizes of the obstacles and four different heights of container opening are tested. Two slender mirrors are installed at the top and the bottom of the transparent chute to reflect the free surface flow and the basal flow image simultaneously to the photographic recording system. Together with the side wall view, image/PIV analysis for the three visible flow fields is performed. With the extra flow profiles and a proposed linear interpolation scheme, we are able to calculate the solid volume fraction along the stream-wise direction in a cost-effective way.
The results show that the effect of the obstacle on the flow field increase both with increasing the Froude number of the upstream flow and the size of obstacle, and rapidly increase when Froude number of the upstream larger than critical value. Moreover, choked flow is occurred at lower Froude number of the upstream flow. The dynamic behaviors in this state are also discussed.
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