摘要
弧形闸门是水利工程中重要的挡水、泄水建筑物,虽然弧形闸门被设计成具有足够的刚度来承受设计水压,但泄水过程中水压的脉动可能会使闸门产生较大的振动,进而造成闸门的破坏。结合湍流模型和流体体积方法(volume of fluid,VOF)建立弧形闸门泄流三维湍流流场数值模型,数值求解采用稳态计算和瞬态计算两个连续的运算步骤进行,以便更好地确定入口处的流速。分别采用k-ε湍流模型和k-ω湍流模型对闸门周围流场和作用在弧形面板上的流体压力进行计算,结果表明:k-ε湍流模型与壁函数相结合的方法不能捕捉到稳定泄流阶段闸门面板上的压力脉动行为,而k-ω湍流模型结合壁面积分不仅能够得到闸门周围的流场变化,而且能准确计算闸门面板上的脉动压力。基于k-ω湍流模型计算结果,分析下游水位变化对闸门周围流场和脉动压力的影响,闸门面板上压力的脉动主要是由于闸门前的漩涡引起的,压力脉动的优势频率取决于闸孔出流形式,与上下游水位差无关,自由出流时的压力脉动优势频率比淹没出流时的大。
Radial gates are important water retaining and discharging structures in hydraulic engineering. Although radial gates are manufactured to have sufficient stiffness for the design water pressure, large vibrations can be produced due to water pressure fluctuation during discharge causing damage to the gate, especially when the dominant frequency of water pressure fluctuation approaches the natural frequency of the gate, which may cause resonance phenomenon.The fluctuating pressure of water flow under local opening on the radial gate panel is a frequent cause of gate vibration. In the past few decades, the hydraulic characteristics such as average pressure distribution, discharge capacity and flow field around the radial gate have been widely studied through numerical simulation, but the fluctuating pressure acted on the panel of the radial gate has not been solved yet. In order to calculate the fluctuating water pressure, a numerical model of 3D turbulent flow field around radial gate was established using two-equation turbulent model and volume of fluid method for free surface. Two consecutive runs of a steady-state run and a timedependent transient run were carried out in order to determine the flow velocity at the inlet. Two turbulence models(i.e., k-ε turbulence model and k-ω turbulence model) were applied in the current study, and the accuracy of the k-εand k-ω turbulence models for the simulation of fluctuating pressure was evaluated and discussed. Based on the k-ωturbulence model, the impact of downstream water level changes on the flow field and fluctuating pressure were investigated.The generation of fluctuating pressure showed close relation to the flow in the boundary layer near the radial gate panel. Reasonable selection of turbulence models and models with near-wall modifications is extremely important for the accuracy of calculating fluctuating pressure results. The combination of k-ε turbulence model and wall function was unable to capture the pressure fluctuating behavior on the gate panel, while the k-ω turbulence model combined with integration method can not only model the flow field around the gate, but also accurately calculate the fluctuating pressure, because of its better performance in the case of boundary-layer flows with a strong adverse pressure gradient.At the stable discharge stage, a large vortex was formed in front of the gate, was the main cause of the fluctuation of water pressure on the gate panel. The amplitude of water pressure fluctuations was influenced by the outflow form of the gate hole and the water level difference between upstream and downstream. Under submerged outflow conditions, a larger water level difference resulted in a higher root mean square value of fluctuating pressure. Conversely, under free outflow conditions, a larger water level difference led to a lower root mean square value of fluctuating pressure. The dominant frequency of fluctuating pressure at each point on the panel under the same operating conditions was identical and was mainly dependent on the orifice flow pattern of the sluice, but independent of the water level difference between upstream and downstream. Under submerged outflow conditions,a large counterclockwise vortex was formed behind the gate, but under free outflow conditions, no obvious vortex will form behind the gate. The dominant frequency of pressure fluctuation under free outflow conditions was higher than that under submerged outflow conditions.
作者
李小超
吴兵兵
周熙
LI Xiaochao;WU Bingbing;ZHOU Xi(School of Hydraulic and Ocean Engineering,Changsha University of Science&Technology,Changsha 410114,China;Key Laboratory of Water-Sediment Sciences and Water Disaster Prevention of Hunan Province,Changsha 410114,China;Key Laboratory of Dongting Lake Aquatic Eco-Environmental Control and Restoration of Hunan Province,Changsha 410114,China;Engineering and Technical Center of Hunan Provincial Environmental Protection for River-Lake Dredging Pollution Control,Changsha 410114,China)
出处
《南水北调与水利科技(中英文)》
北大核心
2025年第1期177-186,共10页
South-to-North Water Transfers and Water Science & Technology
基金
国家自然科学基金项目(51309038)
湖南省教育厅优秀青年项目(19B014)。
关键词
弧形闸门
泄流
湍流模型
脉动压力
漩涡
radial gate
discharge
turbulence model
fluctuating pressure
vortex
作者简介
吴兵兵(1999-),男,安徽合肥人,主要从事水流与结构相互作用研究。E-mail:2465608138qq.com;通信作者:李小超(1981-),男,湖南郴州人,副教授,博士,主要从事水流与结构相互作用研究。E-mail:36633593@qq.com。
