A Study on Nonlinear Thermodynamic Characteristics of Turbulent Transport
A Study on Nonlinear Thermodynamic Characteristics of Turbulent Transport
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DOI：
10.1002/cjg2.779
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发表时间：
2005-11
期刊：
影响因子：
--
通讯作者：
H. Zuo;Yinqiao Hu
中科院分区：
文献类型：
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作者：
H. Zuo;Yinqiao Hu
由于湍流输运是热力学中的一种不可逆过程，应用非线性热力学对其特性进行了研究。当热力流动展开为平衡态参考态附近的热力泰勒级数时，湍流输运系数为平均变量梯度的泰勒级数。湍流输运系数的线性项与雷诺湍流闭合格式中K闭合的湍流输运系数的线性项相对应，而湍流输运系数的非线性项是系统偏离热力学平衡态所引起的非线性效应。湍流输运系数的线性项是正定的，湍流输运使系统趋于均匀。当系统处于远离热力学平衡态的非线性区时，非线性项可能变负且大到足以使湍流输运系数为负值，这称为负梯度湍流输运。湍流输运系数的热力学特性可以为湍流提供热力学闭合方案。根据最小熵产生定理，得到泰勒级数的系数之间的递推关系。利用这种递推关系，可以大大减少确定泰勒级数所需实验观测的泰勒级数系数的个数。
For the turbulent transport is a kind of irreversible process in thermodynamics, the nonlinear thermodynamics was applied for studying its characteristics. The turbulent transport coefficients are Taylor series of gradient of averaged variables, when the thermodynamic flows are expanded in Taylor series of the thermodynamic forces in the neighborhood of reference state of the equilibrium state. And the linear term of the turbulent transport coefficient corresponds with the turbulent transport coefficient of K closure in Reynolds turbulence closure scheme, and the nonlinear term of the turbulent transport coefficient is the nonlinear effect caused by the departure of system from its thermodynamic equilibrium state. The linear term of the turbulent transport coefficient is positive definite and the turbulent transport makes the system homogenous. When the system is in the nonlinear region far from its thermodynamic equilibrium state, the nonlinear term may become negative and huge enough to make the turbulent transport coefficient negative, this is called as negative gradient turbulent transport. The thermodynamic characteristics of turbulent transport coefficient can provide a thermodynamic closure scheme for the turbulent flow. Based on the minimum entropy production theorem, a recursive relation among the coefficients of Taylor series will be obtained. Utilizing this recursive relation, we can reduce greatly the number of Taylor series coefficients that need to be observed by experiment for determining the Taylor series.