Study on Circular Jet Issuing along Cylinder or Pipe Wall

沿圆筒或管壁发出圆形射流的研究

• 批准号: 09650215
• 负责人: NAKASHIMA Masahiro
• 金额: $ 1.98万
• 依托单位: Kagoshima National College of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09650215/
• 关键词: Turbulent; Circular Jet; Hot Wire Anemometer; Circular Wall; 計測

The circular jet which issues along the outer wall and in the longitudinal direction of the cylinder has been investigated in this paper. Especially, attention is focussed on the unsteady structure of the flow field where the wall jet separates at the down stream location far form the exit. In order to reveal this unsteady property the wavelet analysis was used. In addition to some ordinary wavelet correlations, the wavelet intermittency was newly introduced Though these wavelet analytic methods the separated flow has been clarified The obtained conclusions as follows.(1) From the results of flatness factor and intermittency factor, the intermittency of the flow appears in outer edge of the jet. This intermittency seems to correspond to the separating flow besides the rolling up flow.(2) In order to reveal the unsteadiness of flow, some wavelet analysis were introduced. From the results of the wavelet transfrom and wavelet auto-correlation, it has been clarified the flow field in the downstream location is unsteady considerably.(3) From the results of wavelet cross-correlation by using two sensors, the large scale structure is seen to pass and grow up.

本文研究了沿圆筒外壁和纵向方向喷出的圆形射流。特别是，人们的注意力集中在流场的非稳态结构上，其中壁射流在远离出口的下游位置分离。为了揭示这种不稳定特性，使用了小波分析。除了一些普通的小波相关性外，还新引入了小波间歇性。通过这些小波分析方法，澄清了分离流，得到的结论如下：(1)从平坦度因子和间歇性因子的结果来看，流动的间歇性出现在射流的外边缘。这种间歇性似乎对应于除了卷起流之外的分离流。(2)为了揭示流动的不稳定性，引入了小波分析。从小波变换和小波自相关的结果可以看出，下游位置的流场是相当不稳定的。(3)从使用两个传感器的小波互相关的结果来看，可以看到大尺度结构通过并长大。