Experimental Study Of Control Method Of Horizontal Circulation And Sedimentation Behind A Spur Dike

Horizontal circulation at the inlet of the upper approaching channel of Three Gorges Project can affect the safety of navigation. Boundary layers will separate along a curved dike causing horizontal circulation regions which affect the overall flow field and increase sedimentation. Separation and increased sedimentation are common phenomena in the projects of water conservancy, sea-route and power station. To solve this problem, the method of "sucking-spouting" water has been put forward by Lin Bingnan, based on the theory of boundary layer control, namely, sucking part of the discharge at the upstream-side of the convex barrier and spouting it at the downstream-side. And, he also put forward another method of flow-deflection.The effects of the two methods of "sucking-spouting" water and flow-deflection on the horizontal circulation were tested experimentally in a 50cm-width flume with a spur dike placed as a barrier. They both can reduce the length and strength of the horizontal circulation regions and reduce the sedimentation volume downstream of the dike. The experimental data was used to relate the size of the horizontal circulation regions and the sedimentation volume to the "sucking-spouting" discharge. And, we also have had the relation between the size of the horizontal circulation regions and the Fr number around the dike for the flow-deflection method.The results of this study show that, using the method of flow-deflection or "sucking-spouting" water, the flow pattern can be improved, the size of the horizontal circulation regions and the sedimentation volume caused by the horizontal circulation can both be reduced. So, they can be adopted to improve the navigation condition of upper approaching channel of Three Gorges Project, which could guarantee the safety of navigation.