论文标题
分析紧张的通道流动中的高阶速度矩
Analysis of high-order velocity moments in a strained channel flow
论文作者
论文摘要
在当前的研究中，使用来自紧张的通道中平面湍流的直接数值模拟（DNS）的数据验证了从湍流场概率密度函数的第五阶速度矩的模型表达式。模型表达式的简单性，缺乏未知系数以及它们对非高斯湍流流的适用性，使这种方法可在基于雷诺平均的Navier-Stokes方程的关闭湍流模型中使用。该研究证实了模型表达式的有效性。它还表明，施加的流量变形改善了流量缓冲区中的五阶矩（包括流动逆转方向）的模型和DNS曲线之间的一致性。该研究揭示了特别奇怪的速度力矩对电网分辨率的敏感性。当必须从DNS收集高阶统计数据时，提出了一个新的长度量表作为壁附近的网格产生的标准，以及以高平均速度梯度为主的其他流动区域。
In the current study, model expressions for fifth-order velocity moments obtained from the truncated Gram-Charlier series expansions model for a turbulent flow field probability density function are validated using data from direct numerical simulation (DNS) of a planar turbulent flow in a strained channel. Simplicity of the model expressions, the lack of unknown coefficients, and their applicability to non-Gaussian turbulent flows make this approach attractive to use for closing turbulent models based on the Reynolds-averaged Navier-Stokes equations. The study confirms validity of the model expressions. It also shows that the imposed flow deformation improves an agreement between the model and DNS profiles for the fifth-order moments in the flow buffer zone including when the flow reverses its direction. The study reveals sensitivity of particularly odd velocity moments to the grid resolution. A new length scale is proposed as a criterion for the grid generation near the wall and in the other flow areas dominated by high mean velocity gradients when higher-order statistics have to be collected from DNS.
