Longitudinal vortices imbedded in turbulent boundary layers. Part 1. Single vortex
Longitudinal vortices imbedded in turbulent boundary layers. Part 1. Single vortex
复制标题
嵌入湍流边界层中的纵向涡旋。
DOI：
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发表时间：
1985
影响因子：
3.7
通讯作者：
P. Bradshaw
中科院分区：
文献类型：
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作者：
I. Shabaka;R. Mehta;P. Bradshaw
本文详细地测量了零压力梯度下低速紊流边界层中的平均流动和紊流度。边界层中有一个孤立的、人工产生的涡。涡是由风洞沉降室底板上的半三角翼产生的，因此进入工作段的涡与原来产生的涡具有相同的环量，而轴向分量速度变化相对于局部平均速度从发电机后面的值大大减小。测量结果表明，嵌入边界层中的涡周围的环流几乎是守恒的，仅由展向分量的表面剪应力减少。因此，受涡流影响的流动区域继续向下游扩展，其横截面尺寸大致与局部附面层厚度成比例。从测得的雷诺应力和各种三重积推导出的涡动粘度的各种分量的特性表明，目前湍流模型中使用的这些量的简单经验相关性不太可能产生详细准确的流动预测。
Detailed mean-flow and turbulence measurements have been made in a low-speed turbulent boundary layer in zero pressure gradient with an isolated, artificially generated vortex imbedded in it. The vortex was generated by a half-delta wing on the floor of the wind-tunnel settling chamber, so that the vortex entering the working section had the same circulation as that originally generated, while axial-component velocity variations were very much reduced, relative to the local mean velocity, from values just behind the generator. The measurements show that the circulation around the vortex imbedded in the boundary layer is almost conserved, being reduced only by the spanwise-component surface shear stress. Therefore the region of flow affected by the vortex continues to grow downstream, its cross-sectional dimensions being roughly proportional to the local boundary-layer thickness. The behaviour of the various components of eddy viscosity, deduced from measured Reynolds stresses, and of the various triple products, suggests that the simple empirical correlations for these quantities used in present-day turbulence models are not likely to yield flow predictions which are accurate in detail.