Near and Far-Field Analysis of an Axisymmetric Fractal-Forced Turbulent Jet
Near and Far-Field Analysis of an Axisymmetric Fractal-Forced Turbulent Jet
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轴对称分形强制湍流射流的近场和远场分析
DOI：
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
O. Buxton
中科院分区：
文献类型：
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作者：
M. Breda;O. Buxton
本文研究了初始条件对轴对称湍流射流近场流动物理特性的影响以及向自相似演化的作用。近场大尺度相干结构的操纵与非圆形的几何形状，如正方形和分形出口的援助。平面PIV和热线风速仪被部署来研究流动的空间和时间。尽管由于不同的出口几何形状的近场流动物理的显着改变，它被发现，朝向自相似性的演变是所有的射流之间的可比性。此外，非平衡耗散被发现之间的24和26当量直径（D_e）下游的射流出口处的平均速度和雷诺应力是自相似的，这表明流动的微观尺度比以前认为的更进一步，以恢复经典的标度律。
In this paper, the role of the initial conditions in affecting the flow physics in the near-field, and the evolution towards self-similarity, of an axisymmetric turbulent jet is examined. The near-field large scale coherent structures are manipulated with the aid of noncircular geometries, such as square and fractal exits. Planar PIV and hot-wire anemometry are deployed to study the flow both spatially and temporally. Despite the significant alteration of the near-field flow physics due to the different exit geometries, it is found that the evolution towards self-similarity is comparable between all jets. Moreover, non-equilibrium dissipation is found between 24 and 26 equivalent diameters (D_e) downstream of the jet exit where mean velocity and Reynolds stresses are self-similar, suggesting the microscales of the flow take much further than previously thought to regain the classical scaling laws.