不同船闸泄水过程限制性中间通航航道流速变化规律

Flow velocity fluctuation law in restricted middle navigable channel with different ship lock discharge modes

针对船闸泄水非恒定流引起的流速变化,尤其是限制性中间航道内的水力要素与非恒定流流量变换、中间航道尺度之间的关系,依托百色通航枢纽中间限制性航道,通过系统物理模型试验探究船闸非恒定流泄水过程与限制性中间航道内流速变化过程之间的关系。结果表明,船闸流量迅速下泄过程中,消能不充分、下泄流量迅速增加以及有界域边界限制是非恒定流泄水波形成的主要原因,并导致中间航道内流速波动;分段泄水曲线可通过减小泄水峰值达到减小最大流速和最大回流流速的目的;在长中间通航航道受沿程能量消耗的影响,中间渠道下游流速波动远小于上游,该特征在中间渠道水流流态达到平稳后仍存在。

Aiming at the problems of the flow velocity fluctuation process caused by the unsteady flow of ship lock discharge, especially the relationships of the hydraulic factors in the restricted middle navigable channel, the transformation of unsteady flow and the corresponding scales, we study the relationship between the unsteady flow discharge process of ship lock and the flow velocity fluctuation process in the restricted middle channel through systematic experiments of physic model based on the restricted middle navigable channel of Baise navigation project. The results show that the main reasons of the generation of unsteady flow discharge wave are attributed to insufficient energy dissipation, the rapid increase of discharge during the ship lock discharge process, and the limited boundaries, which cause the flow fluctuation. By reducing the peak value of the fragmented time-discharge curve, the maximum velocity and maximum inverse velocity decrease. In the long restricted middle navigable channel, due to the energy consumption, the velocity fluctuation in the downstream is much smaller than that in the upstream, which still exists after the flow pattern reaches a steady state.