各向异性密度流模型及其验证

An anisotropic buoyant turbulence model and its validation

针对密度流流动各向异性的特性,采用非线性k-ε模式求取雷诺应力,结合RNG模型及浮力修正建立了三维密度流模型。应用该三维模型计算了水库温差异重流,分析了温差异重流演进过程,并就流速分布与水温下泄过程与实测资料进行了比较。结果表明,所建模型由于引入非线性RNG模式,能有效反映密度流的各向异性特性,较好地模拟了流场和温度场强烈耦合的水库温差异重流,能准确预测温度分层过程与异重流潜行时间,具有较高精度。

A 3D numerical model combining the Re-Normalization Group （RNG） k-ε turbulent model, the buoyant correction and the non-linear Reynold stress model is developed to simulate density current, and suitable for solving the anisotropic flow problems. The evolution of the density current formed by temperature variance in reservoirs is simulated by the model. The simulated velocity distribution and temperature variation are compared well with the observations. The result indicates that the model can capture the nonistropical characteristics of the density current effectively, simulate the exact flow field as well as the temperature distribution accurately, and predict the time interval between the density current＇s stratification and diving process precisely.