AN EXPERIMENTAL-STUDY OF A TURBULENT VORTEX RING
AN EXPERIMENTAL-STUDY OF A TURBULENT VORTEX RING
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DOI：
10.1017/s0022112090001562
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发表时间：
1990-02-01
影响因子：
3.7
通讯作者：
COLES, D
中科院分区：
文献类型：
--
作者：
GLEZER, A;COLES, D
一个具有相对较薄核心的湍流漩涡环是通过从浸没板的孔中瞬间喷射而在水中形成的。所需的脉冲由加压储层提供，并由快速可编程电磁阀控制。研究的主要目的是验证系综平均所定义的平均流的相似特性，并找到相应的非稳态相似坐标下平均涡量、湍流能量等量的分布。在双通道跟踪激光多普勒测速仪的辅助下，测量了旋涡的速度场。通过发展一种双变量签名识别技术，克服了单个环轨迹中的色散问题。研究发现，在涡核附近湍流强度最大，至少在近尾迹处径向分量不可忽略。环状结构的缓慢生长是由夹带比去夹带稍微多一点控制的。一个重要的推论是，生长过程和湍流产生过程可能涉及在方位面上包裹在核心周围的二次涡。
A turbulent vortex ring having a relatively thin core is formed in water by a momentary jet discharge from an orifice in a submerged plate. The necessary impulse is provided by a pressurized reservoir and is controlled by a fast programmable solenoid valve. The main aim of the research is to verify the similarity properties of the mean flow, as defined by ensemble averaging, and to find the distribution of mean vorticity, turbulent energy, and other quantities in the appropriate non-steady similarity coordinates. The velocity field of the vortex is measured for numerous realizations with the aid of a two-channel tracking laser-Doppler velocimeter. The problem of dispersion in the trajectories of the individual rings is overcome by development of a signature-recognition technique in two variables. It is found that the turbulence intensity is largest near the vortex core and that at least the radial component is not negligible in the near wake. The slow growth of the ring structure is controlled by a slight excess of entrainment over de-entrainment. An important inference is that the growth process and the process of turbulence production probably involve secondary vortices wrapped around the core in azimuthal planes.