小浪底河段浑水流动的三维数值模拟

Numerical simulations of 3-D flows in the reach of the Xiaolangdi Project

基于湍流随机理论,针对黄河中游小浪底工程建成前的河段水沙流动特点,建立了河流的三维水沙流数学模型。在此模型中,采用各向异性湍流的Reynolds应力数值格式和自由面位置的Poisson方程,并将精细壁函数应用于边壁处理。建立了床面附近含沙量表达式,将传统的床沙级配控制方程推广到三维模型。在贴体坐标系下,用此数学模型计算了此河段的含沙量和流速沿河宽和垂线分布,计算结果与原型实测成果基本吻合,从而证明了此模型的可行性,以及计算方法和程序的可靠性。

A 3-D silt-laden mathematical model based on stochastic turbulence theory was developed to analyze the flows in the river reach of the Xiaolangdi project. The scheme calculates the Reynolds stresses for anisotropic turbulent flows and solves a pressure Poisson equation for the free surface flow with a refined wall function for the solid boundaries. The sediment carrying capacity near the bed surface was estimated with the traditional equations for sorting of the bed material extended to 3-D geometries. In body-fitted coordinates, simulations of silt concentrations and velocity distributions at various cross-sections in the reach, agree well with data from physical models, which indicate this model, and this computational method and program are reliable.