下游高水位条件下导流洞改建为旋流竖井式泄洪洞的水力学问题研究

导流洞改建为旋流竖井式永久泄洪洞后，由于泄洪标准提高，对于某些大型工程，如小湾、溪洛渡等会遇到下游水位过高的技术难题，由于洞顶被淹没，泄洪洞内会出现水跃、不稳定气囊等不利流态，必须采取适当的工程措施进行调整与控制。作者在小湾工程大型导流洞改建为旋流竖井式泄洪洞的试验研究中提出采用竖向压板技术优化洞内流态，并以多孔平板技术解决导流洞出口的排气问题，使这一难题得到较好解决。本文着重对竖向压板的作用原理进行理论分析与探讨。

Study on hydraulic problems in reconstruction of diversion tunnels into permanent vortex shaft spillways in condition of high tail water level

Unfavorable hydraulic phenomena might occur to the diversion tunnel if being reconstructed as a permanent vortex shaft spillway, in case of high tail water level. The phenomena include flow pattern changing from free surface flow to pressure flow, hydraulic jump and unsteady air bags etc. To solve these problems a vertical plate followed by a perforated cover panel installed at the end of the tunnel is proposed to control the flow pattern and release the air entrained. The functions and the principle of this vertical plate are theoretically and experimentally studied.