向家坝升船机下游引航道口门区水力波动特性原型观测

Prototype observation of hydraulic fluctuation characteristics at entrance of approach channel downstream of Xiangjiaba ship lift

向家坝水电站坝下河势及地形条件复杂,枢纽泄洪时升船机下游引航道口门区波动现象较为显著。原型观测表明,表孔泄洪时消力池内形成波状水跃,并以短波形式传向下游。受多种复杂条件影响,坝下河道纵向高频波动在升船机下游引航道口门区附近转变为横向振荡波,对船舶航行安全影响显著。通过分析向家坝枢纽不同泄洪流量下升船机下游引航道口门区水力波动特性原型观测结果可知,表孔泄洪是导致引航道口门区短波振荡的主要因素,且其泄量与口门区水力波动呈线性关系,而电站泄流和中孔泄洪利于降低口门区水力波动。

The river regime and topographic conditions of Xiangjiaba Hydropower Station downstream are complex,and the fluctuation at the entrance of the approach channel downstream of the ship lift is larger during the flood discharge.Prototype observations show that a wavy water jump is formed in the stilling basin when the surface hole is discharged,and it is transmitted downstream in the form of short waves.Affected by a variety of complex conditions,the longitudinal high-frequency fluctuations of the river under the dam transform into lateral oscillation waves near the entrance area of the approach channel downstream of the ship lift,which has a significant impact on the safety of ship navigation.Analyzing the prototype observation results of the hydraulic fluctuation characteristics of the approach channel entrance area of the downstream approach channel of the Xiangjiaba Junction under different flood discharge flows,we know that the surface flood discharge is the main factor leading to short-wave oscillations in the approach channel entrance area,and its discharge is linearly related to the fluctuation of the entrance area.Moreover,the power station discharge and the middle hole flood discharge have a positive effect on reducing the hydraulic fluctuation in the entrance area.