Vortex induction and mass entrainment in a small-aspect-ratio elliptic jet
Vortex induction and mass entrainment in a small-aspect-ratio elliptic jet
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DOI：
10.1017/s0022112087001587
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发表时间：
1987-06
影响因子：
3.7
通讯作者：
Chih-Ming Ho;E. Gutmark
中科院分区：
文献类型：
--
作者：
Chih-Ming Ho;E. Gutmark
通过使用小展弦比椭圆射流，发现了一种被动增加卷吸的技术。椭圆射流的卷吸比是圆形射流或平面射流的数倍。非对称相干结构的自感应导致了方位向扭曲，这是将大量周围流体吞没到喷流中的原因。在椭圆射流中，初始稳定过程中一个有趣的特征是喷嘴周围剪切层的厚度变化。结果表明，不稳定频率随初始动量厚度的增大而增大，而初始动量厚度与最大涡度有关。湍流特性也被检查，发现在长轴和短轴平面上有很大的不同。
A passive technique of increasing entrainment was found by using a small-aspect-ratio elliptic jet. The entrainment ratio of an elliptic jet was several times greater than that of a circular jet or a plane jet. The self-induction of the asymmetric coherent structure caused azimuthal distortions which were responsible for engulfing large amounts of surrounding fluid into the jet. In an elliptic jet, an interesting feature in the initial stability process is that the thickness of the shear layer varies around the nozzle. The data indicated that instability frequency was scaled with the thinnest initial momentum thickness which was associated with the maximum vorticity. Turbulence properties were also examined and were found to be significantly different in the major- and minor-axis planes.