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为了研究喷管射流噪声特性问题,应用丹麦B.K.公司3560C型多用途分析系统,对轴对称直喷管在不同压比下产生的亚音速和跨音速射流噪声进行了测量。并对外流场轴向和截面流动特性进行了测量和分析,确定了测量噪声探头放置位置,比较了离模型截面不同位置处的噪声。给出频率在5000Hz内噪声变化的规律,发现在低频时随着静压比的增加噪声急剧增强。在接近给定实验静压比值前,噪声达到最大,并起伏振荡,在此值以后,噪声变得平缓而具有减弱的趋势。
In order to study the characteristics of nozzle jet noise, the 3560C multi-purpose analysis system of Danish company B.K. was used to measure the subsonic and transonic jet noise generated by the axially symmetric straight nozzle under different pressure ratios. The axial and cross-sectional flow characteristics of the external flow field were measured and analyzed. The position of the noise probe was determined and the noise at different positions in the cross section of the model was compared. Given the frequency of 5000Hz frequency changes in the law and found that at low frequencies with the static pressure ratio increased sharply increased noise. Before approaching a given static pressure ratio, the noise reaches the maximum and oscillates undulating. After this value, the noise becomes gentle and tends to decrease.