Experimental analysis of the precessing vortex core in a free swirling jet
Experimental analysis of the precessing vortex core in a free swirling jet
复制标题
自由旋流射流进动涡核的实验分析
DOI：
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发表时间：
2007
期刊：
影响因子：
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通讯作者：
A. Coghe
中科院分区：
文献类型：
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作者：
F. Martinelli;A. Olivani;A. Coghe
利用激光多普勒测速仪（LDV）和粒子图像测速仪（PIV）对常温常压下自由旋转空气射流中旋进涡核（PVC）不稳定性进行了实验研究。两个参数的研究被认为是不同的涡流参数和雷诺数。考虑的参数范围允许研究条件的强进动以及不稳定的开始和解决。平均速度和标准偏差的配置文件，功率谱密度函数和概率密度函数的轴向和切向速度分量。平均以及瞬时PIV图被认为是在流场结构的表征和检测的瞬时位置的涡中心。速度PDF和功率谱的联合分析表明，PVC对速度场的全局统计的贡献可以与真实流动湍流的贡献适当分离，从而对进动现象的物理特性提供额外的见解。在所研究的条件范围内得到的结果表明，真实的湍流强度与旋流参数无关。
An experimental analysis of the precessing vortex core (PVC) instability in a free swirling jet of air at ambient pressure and temperature is performed by means of laser Doppler velocimetry (LDV) and particle image velocimetry (PIV). Two parametric studies are considered, varying the swirl parameter and the Reynolds number. The range of parameters considered allowed to study conditions of strong precession as well as the inception and settlement of the instability. Mean velocity and standard deviation profiles, power spectral density functions and probability density functions for the axial and tangential velocity components are presented. Average as well as instantaneous PIV maps are considered in the characterization of the flowfield structure and detection of the instantaneous position of the vortex center. Joint analysis of velocity PDFs and power spectra shows that the PVC contribution to the global statistics of the velocity field can be properly separated from the contribution of the true flow turbulence, giving additional insight to the physics of the precession phenomenon. The results obtained in the explored range of conditions indicate that the true turbulence intensity is not dependent on the swirl parameter.