基于Navier-Stokes方程和RNG k-ε湍流模型,采用流体体积函数法(Volume of Fluid,VOF)追踪非线性自由界面,对比趾墩悬栅联合消能与单一悬栅消能2种方式的水力特性差异,模拟水跃过程产生的大尺度紊动及水汽两相的强烈掺混作用。获得消力池内精细流场结构及边壁所受压力变化,以此对紊动特性及压力分布规律进行研究。结果表明:趾墩悬栅联合消能结构显著增加了渥奇段内水体紊动强度与规模,其中0.4＜h*＜0.8(h*为相对水深)范围内紊动强度相较单一悬栅显著增加,沿程衰减显著;消力池底板动水压力呈现明显波动,其平均动水压力相比单一悬栅略有降低;压力脉动峰值位于0.3＜xp＜0.4(xp为沿程相对位置),其动压力系数为消力池底板最大动水压力系数的2.0~2.4倍。研究成果可为消能机理的研究提供可靠依据。
Abstract
The differences in hydraulic characteristics between two energy dissipation approaches, combination of diversion pier and suspended grid and single suspended grid, were investigated by tracking the nonlinear free surface using the VOF method based on the Navier-Stokes equation. The large-scale turbulence and intensive air entrainment in the hydraulic jump were simulated. On this basis, the detained flow structure and wall pressure in the stilling pool were obtained for analyzing the turbulence and pressure distribution. Results illustrated that the joint energy dissipator significantly increased the turbulent intensity and fluctuating scale of water body in the paraboloid of stilling basin. The turbulence intensity, which decayed remarkably along the flow direction, was highly improved compared with the control scheme (single suspended grid) for relative depth h* in the range from 0.4 to 0.8. Hydrodynamic pressure on the base slab of stilling pool fluctuated notably, and the average pressure reduced slightly compared with that in the control scheme. The peak of pressure fluctuation is located nearby 0.3＜xp＜0.4(xp is the relative location), and the dynamic pressure coefficient is 2.0~2.4 times of the maximum value on the base slab of the pool.
关键词
水跃 /
悬栅 /
联合消能工 /
数值模拟 /
紊动强度 /
压力系数
Key words
hydraulic jump /
suspended grid /
joint energy dissipator /
numerical simulation /
turbulent intensity /
pressure coefficient
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基金
国家自然科学基金项目(51469031);新疆维吾尔自治区高校科研计划创新团队项目(XJEDU2017T004)
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