Study On Flow Deceleration Through Frames Made Of Hollow Tetrahedron

Based on the results of present investigation, by theoretic analysis and physical model experimentation and numerical experimentation, the deeper research for flow deceleration through Frames made of hollow tetrahedrons is carried out. The main contents are as follows:(l)Through theoretic analysis and flume experiments, the characteristic of water resistance through Frames is researched, and transforms relation between resistance coefficients and Manning's roughness coefficients is established, and then experiential formula of Manning's roughness coefficients is fitted.(2)Before and after the frames are placed the velocity vertical distribution in the same cross-section are measured by ADV. The results indicate that after the frames are placed the mean velocity and turbulent intensity near bed are reduced, and vertical distribution of turbulent intensity is more uniform.(3)Through dimension analysis, factors that affect the flow deceleration through frames are discussed. Based on flume experiments, this study indicates the velocity near the bed decreases as the l/H increases, and the â–³l/H decreases, the influence of frames height on the effect of velocity near the bed is not distinct(4)By 2-D mathematical model, patterns of flow through frames are analyzed and the influence of different frame formations on the protection zone is researched, mean velocity in vertical decreases and protection zone enlarges as the l/H, b/B and a /H increases. Therefore we should choose length, width, height and interval of frames according to water height and demand of velocity.The results can be used for reference to the design of bank protection works.