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On mean flow universality of turbulent wall flows. I. High Reynolds number flow analysis
Journal of Turbulence ( IF 1.9 ) Pub Date : 2018-12-02 , DOI: 10.1080/14685248.2019.1566736
Stefan Heinz 1
Affiliation  

ABSTRACT The universality and mathematical physical structure of wall-bounded turbulent flows is a topic of discussions over many decades. There is no agreement about questions like what is the physical mean flow structure, how universal is it, and how universal are theoretical concepts for local and global flow variations. These questions are addressed by using latest direct numerical simulation (DNS) data at moderate Reynolds numbers Re and experimental data up to extreme Re. The mean flow structure is explained by analytical models for three canonical wall-bounded turbulent flows (channel flow, pipe flow, and the zero-pressure gradient turbulent boundary layer). Thorough comparisons with DNS and experimental data provide support for the validity of models. Criteria for veritable physics derived from observations are suggested. It is shown that the models presented satisfy these criteria. A probabilistic interpretation of the mean flow structure shows that the physical constraints of equal entropies and equally likely mean velocity values in a region unaffected by boundary effects impose a universal log-law structure. The structure of wall-bounded turbulent flows is much more universal than previously expected. There is no discrepancy between local logarithmic velocity variations and global friction law and bulk velocity variations. Flow effects are limited to the minimum: the difference of having a bounded or unbounded domain, and the variation range of mean velocity values allowed by the geometry.

中文翻译:

关于湍流壁流的平均流动普遍性。一、高雷诺数流分析

摘要 壁面湍流的普遍性和数学物理结构是几十年来讨论的主题。对于物理平均流量结构是什么、它有多普遍以及局部和全球流量变化的理论概念有多普遍等问题,没有达成一致意见。通过使用中等雷诺数 Re 的最新直接数值模拟 (DNS) 数据和高达极端 Re 的实验数据来解决这些问题。平均流结构由三个典型的壁面有界湍流(通道流、管道流和零压力梯度湍流边界层)的分析模型来解释。与 DNS 和实验数据的彻底比较为模型的有效性提供了支持。建议了从观察中得出的真实物理学的标准。结果表明,所提出的模型满足这些标准。平均流动结构的概率解释表明,在不受边界效应影响的区域中,等熵和等可能平均速度值的物理约束强加了通用对数定律结构。壁面湍流的结构比以前预期的要普遍得多。局部对数速度变化与全局摩擦定律和整体速度变化之间没有差异。流动效应被限制在最小值:有界域和无界域的差异,以及几何允许的平均速度值的变化范围。平均流动结构的概率解释表明,在不受边界效应影响的区域中,等熵和等可能平均速度值的物理约束强加了通用对数定律结构。壁面湍流的结构比以前预期的要普遍得多。局部对数速度变化与全局摩擦定律和整体速度变化之间没有差异。流动效应被限制在最小值:有界域和无界域的差异,以及几何允许的平均速度值的变化范围。平均流动结构的概率解释表明,在不受边界效应影响的区域中,等熵和等可能平均速度值的物理约束强加了通用对数定律结构。壁面湍流的结构比以前预期的要普遍得多。局部对数速度变化与全局摩擦定律和整体速度变化之间没有差异。流动效应被限制在最小值:有界域和无界域的差异,以及几何允许的平均速度值的变化范围。局部对数速度变化与全局摩擦定律和整体速度变化之间没有差异。流动效应被限制在最小值:有界域和无界域的差异,以及几何允许的平均速度值的变化范围。局部对数速度变化与全局摩擦定律和整体速度变化之间没有差异。流动效应被限制在最小值:有界域和无界域的差异,以及几何允许的平均速度值的变化范围。
更新日期:2018-12-02
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