Turbulence structures in high-speed air flow along a thin cylinder
Turbulence structures in high-speed air flow along a thin cylinder
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DOI：
10.1080/14685248.2017.1298769
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发表时间：
2017-03
影响因子：
1.9
通讯作者：
T. Ohta
中科院分区：
文献类型：
--
作者：
T. Ohta
摘要利用直接数值模拟方法，在较宽的雷诺数半径范围内，再现了沿沿着圆柱单丝纱线轴向的湍流流动。在最薄圆柱体的模拟中，摩擦系数与先前发表的公式一致。甚至在最薄的圆柱体周围也检测到一对高速和低速条纹，从而根据分析的湍流统计数据确认湍流持续存在。即使只有一对条纹周围的圆柱体被检测到，湍流结构的特性，如平均条纹间距的基础上的粘性长度尺度，是相同的平板上的流动。有人发现，摩擦系数的变化的方式，保持流动的结构特征，一致的观点，湍流结构的普遍特征存在。
ABSTRACT Turbulent flow in the axial direction along a cylinder representing a monofilament yarn was reproduced for a relatively wide range of radius Reynolds numbers using direct numerical simulations. In the simulation of the thinnest cylinder, the friction coefficient agreed with a previously published formula. A pair of high- and low-speed streaks was detected around even the thinnest cylinder, whereby it was confirmed that turbulence was sustained according to the analysed turbulence statistics. Even when only a single pair of streaks around the cylinder was detected, the characteristics of the turbulence structures, such as the mean streak spacing based on the viscous length scale, were the same as those in flows over a flat plate. It was found that the friction coefficient changes in a way that maintains the structural characteristics of the flow, consistent with the view that universal characteristics of turbulence structures exist.