On the development of large-scale structures of a jet normal to a cross flow
On the development of large-scale structures of a jet normal to a cross flow
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DOI：
10.1063/1.1347960
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发表时间：
2001-02
影响因子：
4.6
通讯作者：
T. Lim;T. New;S. Luo
中科院分区：
文献类型：
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作者：
T. Lim;T. New;S. Luo
众所周知，涡环是自由射流近场中的主要流动结构，这使得许多研究人员认为涡环也存在于横流射流中。以前的研究假设，这些涡环在向下游对流时变形和折叠，最终在喷流柱的上游和背风侧形成涡环。在这篇论文中，我们通过在射流出口周围的关键位置释放染料，对水中JICF的涡旋结构进行了全新的观察。结果表明，JICF内不存在环状涡，涡环折叠形成涡环的假设不能反映实际流动行为。研究发现，在射流出口处存在一个反向旋转的涡对(CVP)可以抑制涡环的形成。相反，涡环是由圆柱涡片或喷流柱的变形直接形成的，而不是通过涡环，即可形成涡环。
It is well known that vortex rings are the dominant flow structures in the near field of a free jet, and this has led many researchers to believe that they also occur in a jet in cross flow (JICF). Previous studies have postulated that these vortex rings deform and fold as they convect downstream, which culminates in the formation of vortex loops at both the upstream and the lee-side of the jet column. In this paper, we take a fresh look at the vortical structures of JICF in water by releasing dye at strategic locations around the jet exit. The results show that there is no evidence of ring vortices in JICF, and the postulation that vortex loops are formed from the folding of the vortex rings does not reflect the actual flow behavior. The presence of a counter-rotating vortex pair (CVP) at the jet exit is found to inhibit the formation of the vortex rings. Instead, vortex loops are formed directly from the deformation of the cylindrical vortex sheet or jet column, without going through the vortex rings, i...