非线性k－ε模型的力学实质探讨

MECHANICAL ANALYSIS OF THE NON-LINEAR k-ε TURBULENCE MODEL

本文运用非线性连续介质力学的变形与本构理论及湍流建模准则作为依据，对非线性ｋ－ε模型的Ｒｅｙｎｏｌｄｓ应力计算表达式进行详尽的分析与探讨，得出针对本构关系而涉及二阶变形率及其Ｏｌｄｒｏｙｄ导数的非线性项是改善涡粘模型又反映脉动结构的各向异性的有效途径，建立各向异性模型应该采用客观物理量，现实性的考虑可以保证附加应力无迹来实现。

According to stres-deformation theory of continum mechanics, the formula of Reynolds stress of non-linear k-ε turbulence model is discussed and analyzed in this paper.We find that it is an effective method to improve the isotroy of the standart k-ε model when second-order terms of deformation rate and its Oldroyd difference are taken into account which is implied by the stress-deformation principle,and only objective variables can be used to formulate Reynolds stress,while the additional terms to Boussinesq assumption should be no trace.Two-dimensional turbulent flow in a slightly-curved duct is numerieallyinvestigated with both of the non-linear and the standart k-ε model than that of the standart one.