k-kl模型在风生混合流中的应用

为了考察k-kl模型在风生混合流的应用效果,将影响其紊动扩散模拟结果的因素归结为3类:一是稳定函数的不同;二是壁函数的不同;三是稳态里查德森数Rist的不同.从这3个方面着手对k-kl模型进行分析,比较各种不同方法对混合层及紊动扩散的影响,并采用国外试验结果来检验数值模拟结果.结果表明:稳定函数的选取对计算结果会有影响,相比之下,较新的模型如CA,CB,CH能得出比传统的MY,KC更精确的结果;抛物改进型的壁函数的结果稍好于抛物线型和对称型壁函数;稳态里查德森数对混合层的发展有重要影响,当它的值增大时,同时刻混合层深度也会增加.

Application of k-kl turbulence model in wind-induced mixing flows

In order to evaluate the application of k-kl turbulence model in wind-induced mixing flows, the factors resulting in different simulated results of turbulent diffusion were categorized into 3 classes: different stability functions, different wall functions and different steady-state Richardson numbers Ri_(st). The k-kl turbulence model was analyzed from the 3 aspects. The influences of different methods on mixing flows and turbulent diffusion were compared. The numerical results were verified by use of the overseas test results. It is found that various stability functions have apparent influences on the calculated results, and the newer models such as CA, CB and CH will give more precise results than the conventional ones such as MY and KC. The improved parabolic wall function will lead to more reasonable results than the parabolic and symmetric wall functions. The steady-state Richardson numbers have great influences on the development of the mixing flows, and when they increase, the depth of the mixing flows will also increases.