摘要
以圆湍射流为对象 ,用修正的周期图法对圆湍射流下游近场的速度场进行了频谱特性分析 ,空气射流的雷诺数为 Re=2 93 8。研究了外界主动声激励对圆湍射流功率谱的影响 ,并与流场显示的结果进行了对照。实验结果表明 ,在圆湍射流混合层内缘与核心区结合部是射流对外界声激励响应最明显的位置。外界声激励对圆湍射流的影响区域集中在射流近场。沿着射流方向 ,在射流出口和核心区尾部之间 ,功率谱分布有一个最大值。
The power spectral density (PSD) characteristics of streamwise velocities in the downstream proximal region ( x/D <10) of the round turbulent jet have been investigated using the modified periodogram method.The Reynolds number based on the gas jet exit mean velocity and the nozzle diameter is 2938.The effects of artificial acoustic excitation on the PSD characteristics of the jet are investigated.Comparisons with the jet flow visualization results are also conducted.The spectral analysis indicates that the adjacent zone between the mixing layer and the potential core are the actively responding position to the acoustic excitation,where the jet coherent structures generated and developed.The results also show that the influence of the acoustic excitation is limited in the proximal region and a maximum PSD value of the streamwise velocities exists between the jet exit and the end of the potential core.
出处
《燃烧科学与技术》
EI
CAS
CSCD
1999年第3期240-245,共6页
Journal of Combustion Science and Technology
基金
国家自然科学基金! (批准号 :5 0 476 0 3 8)
清华大学煤的清洁燃烧技术国家重点实验室资助
关键词
圆湍射流
频谱分析
湍流拟序结构
激光测试
Round turbulent jet,Strouhal number,Spectral analysis,Turbulent coherent structures,Laser diagnostic technique
