DIKE FORMATION WITH SUBMERGED VANE

查看全文 作　　者：Umesh P. [1]GUPTA;C. S. P. [2]OJHA;Nayan [3]SHARMA 机构地区：[1]Morphology Directorate, Central Water Commission, New Delhi, India;[2]Civil Engg. Dept., Indian Institute of Technology, Roorkee, India Prof.;[3]WRD&M Dept., Indian Institute of Technology, Roorkee, India Prof. 出　　处：《International Journal of Sediment Research》索引2006年第21卷第3期,共9页 摘　　要：Submerged vanes are submerged foils constructed in a river at an angle of attack to induce horizontal circulation in the downstream flow. The initial height of vanes is 0.2 – 0.4 times the local water depth (d) at the design stage. Its length expressed as a multiple of the height to length ratio (H/L) normally is 0.25 to 0.5. With the use of a submerged vane in straight channels, dikes (heaps of sediment) were formed downstream. At an optimal angle of attack of 40o and at a Froude number of 0.25, the formation of the dike starts at some distance from the trailing edge of the rectangular and trapezoidal submerged vanes with a collar. A significant scour hole results at the trailing edge of a vane with a collar. A typical dike formed along the vane on the suction side with a symmetric bell-shaped profile. The dike formation phenomenon triggered by a vane close to the bank-line at a flow with a relatively higher Froude number, such as 0.25, does not seem to follow a straight alignment, but has a sort of curvilinear shape bent towards the suction side. The dike formation process for a flow with a smaller Froude number, such as 0.13, is observed to not be appreciable. With the same installation height of H, a vane without a collar was dislodged by the flow at a Froude number of 0.25, whereas it was stable at a Froude number of 0.13. 关 键 词：堤防 环流量 冲刷作用 防汛