湍流速度和耗散率联合几率密度函数的输运方程

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The Evolution Equation of Joint Pdf of Turbulent Velocity and Dissipation

摘要: 根据湍流动能耗散率满足对数正态分布的假定,给出耗散率的随机模型,并对速度的Langevin模型^[6]进行了修正,从而建立起完全封闭的湍流速度和耗散率联合几率密度函数的输运方程.为检验模型的可靠性,用Monte Carlo方法对输运方程进行了数值求解,给出衰变湍流和均匀剪切湍流的满意结果.

Abstract: According to the hypothesis that the dissipation of turbulent kinetic energy satisfies log-normal distribution, a stochastic model of dissipation is provided and the Langevin modef^[6] of velocity is modified. Then a joint Pdf equation of turbulent velocity and dissipation is derived. We solve numerically the joint pdf equation using Monte Carlo method and obtain satisfactory results for decaying turbulence and homogeneous turbulent shear flow. The preliminary results show that the model is well working.

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