泄洪洞中墩水翅现象的试验研究

为了研究泄洪洞中墩的水翅问题,设计了2种中墩方案并进行了1∶40的水工模型试验.试验结果表明:(a)单洞结构尺寸较大的泄洪洞在进口段加设中墩后,由于水头高、流速大,会发生水翅冲击顶部和边墙的现象,并会对泄洪洞的安全运行构成威胁;(b)水翅现象与中墩的几何参数和水面下凹深度和长度有关,水翅长度随中墩长度的减小和水面下凹长度的增加而增加,水翅高度随中墩长度的减小和水面下凹深度的增加而增加;(c)水面下凹深度与中墩几何参数也有密切关系.

Experimental study on water-wing phenomena for middle-piers of discharge tunnels

Two schemes for middle-piers were designed,and hydraulic model tests with the scale of 1:40 were performed to investigate the water-wing phenomena.Some conclusions are drawn as follows: the placement of middle-piers at the inlets of single-passage,large size discharge tunnels may lead to the occurrence of water-wings,which strike the top and side wall of the tunnels due to high water head and high flow velocity and threaten the operation of the discharge tunnels;the water-wing phenomenon is closely related to the geometric parameters of the middle-piers and the extent of concave-surfaces around the end of the middle-piers,and with the decrease of the length of the middle-piers and the increase of length of the concave-surfaces,the length of water-wings increases,while the height of water-wings increases as the length of the middle-piers decreases and the depth of the concave-surfaces increases;the extent of the concave-surfaces around the end of the middle-piers is also closely related to the geometric parameters of the middle-piers,and the longer the middle-piers,the greater the depth of the concave-surfaces.