Jet wave amplification in organ pipes
Jet wave amplification in organ pipes
复制标题
风琴管中的射流波放大
DOI：
10.1121/1.423113
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发表时间：
1998
期刊：
影响因子：
--
通讯作者：
S. Yoshikawa
中科院分区：
文献类型：
--
作者：
S. Yoshikawa
通过烟状射流的流动显示，估计了气流在口上方的放大系数，其中速度范围为7 ~ 33 m/s，雷诺数为1000 ~ 5000，探测频率为130 ~ 580 Hz。两种型号的射流长度分别为15.8和10.2 mm，射流厚度均为2.2 mm。通过将可视化的射流包络线与简化的理论包络线进行比较，进行了估计。包络是通过数字记忆帧的OR求和来可视化的，显示了以每秒1440帧的速度拍摄的瞬时偏转。此外，基于包络线的估计得到了定义为声位移幅值的口场强度。然后用热线风速计测量口场强度，其值与估计结果吻合得很好。估计器官射流的放大系数为0.26 ~ 0.18 (1/mm)；口场强度为0.5 ~ 1.5 mm。我们的风琴管射流中放大系数与吹速关系的无量纲化表示与基于射流不稳定性线性化空间分析的理论曲线大致一致。
The amplification factor of an air jet waving over the mouth is estimated from flow visualization of the smoked jet, where the velocity ranges from 7–33 m/s, the Reynolds number from 1000–5000, and the sounding frequency from 130–580 Hz. The jet length is 15.8 and 10.2 mm in two models, while the jet thickness is 2.2 mm in both. The estimation is carried out by comparing the visualized envelope of jet waves with a simplified theoretical one. The envelope is visualized by the OR summation of the digitally memorized frames showing the instantaneous deflection taken with a speed of 1440 frames per second. Furthermore, the strength of mouth field defined as the acoustic displacement amplitude is derived from the envelope‐based estimation. A hot‐wire anemometer is then applied to measure this mouth‐field strength, whose value shows a good agreement with the estimated result. The amplification factor of organ jets was estimated as 0.26 to 0.18 (1/mm); the mouth‐field strength as 0.5 to 1.5 mm. A nondimensionalized representation of the relation between the amplification factor and the blowing velocity in our organ‐pipe jets roughly agrees with the theoretical curve based on the linearized spatial analysis of jet instability.