Role of initial conditions on noise from underexpanded pipe jets
Role of initial conditions on noise from underexpanded pipe jets
复制标题
初始条件对膨胀管射流噪声的影响
DOI：
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
K. Srinivasan
中科院分区：
文献类型：
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作者：
T. Jothi;K. Srinivasan
对不同剪切层厚度的欠膨胀空气射流声辐射进行了实验研究。初始剪切层厚度的变化是通过允许射流通过不同长度的管道离开来实现的。本研究考虑的管道长度范围为1≤L/D≤6。管道射流的压力比从3变化到7，对应于完全膨胀的射流马赫数1.35≤Mj≤1.92。声辐射的特征在于整体声压级、指向性、音调和宽带冲击相关噪声。管道射流中初始剪切层厚度的增加导致尖叫音幅度的减小（最多20 dB），并增加宽带冲击相关噪声级。与较长的管道射流相比，较短的（L/D）管道射流的湍流混合噪声水平更高。较长的管道射流表现出更多的尖叫模式，而较短的管道射流只显示一个或两个尖叫模式。尖叫的频率和...
An experimental investigation of acoustic radiation from underexpanded air jets of different shear layer thicknesses has been performed. The initial shear layer thickness variation is achieved by allowing the jet to exit through pipes of various lengths. The lengths of the pipes considered for the present study are in the range 1≤L/D≤6. The pressure ratio of the pipe jets is varied from 3 to 7 corresponding to fully expanded jet Mach numbers of 1.35≤Mj≤1.92. Acoustic radiation is characterized in terms of overall sound pressure level, directivity, tonal, and broadband shock associated noise. Increase in initial shear layer thickness in pipe jets results in the decrease of screech tone amplitude (by up to 20 dB), and increase in broadband shock associated noise level. Turbulent mixing noise levels are higher for shorter (L/D) pipe jets compared to longer ones. Longer pipe jets exhibit more number of screech modes while the shorter pipe jets show only one or two screech modes. The screech frequency and the ...