Control of the Radiation of Screech Tone by Cavity Tone Generated in the Supersonic Jets

超音速喷气机空腔音对尖叫音辐射的控制

• 批准号: 09650187
• 负责人: UMEDA Yoshikuni
• 金额: $ 2.11万
• 依托单位: KYOTO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09650187/
• 关键词: Supersonic Jet; Cavity Tone; Screech Tone; Reduction of Noise

In recent years, a supersonic passenger airplane of next generation is developping. The supersonic jets will be used as the thrust of this airplane. However, it is well known that very strong sound waves called screech tone is radiated. This screech tone is generated by the feedback loop consisting of downstream-convecting coherent vortical structures around the jet and upstream-propagating sound waves in the ambient. The radiation of such very intense noise from the supersonic jets will cause the serious noise pollution near the airports as well as the fatigue failure of the airplanes. Therefore, this experimental study was performed to clarify the possibilty of the noise reduction radiated from supersonic jets. The acoustical characteristics of the cavity tone and the screech tone radiated by the jet issuing from a rectangular nozzle with cavity were investigated in the last year. In this year, the acoustical characteristics of the tones radiated by the supersonic jet discharged from … More the circular nozzle with cavity were investigated. From the experimental results, the following things were found : (1) The screech tone whose frequency is higher than that of cavity tone is effectively reduced. (2) The sound pressure level (SPL) of the screech tone radiated from the jets exhausting from the nozzle with cavity becomes lower than that of the screech tone radiated from the free jet discharging from the nozzle without cavity by about 30dB at most. The SPL of the cavity tone is lower than that of the screech tone radiated from the free jet issuing from the nozzle without cavity by about 20dB at most. (3) When the length of the cavity is 1.2 times the nozzle diameter, one of two resonance frequencies, 11.5kHz and 14.0kHz, is appeared. When the frequency of the cavity tone of 11.5kHz is appeared in the pressure ratio range higher than 3.5, the frequency is changed into 14.0kHz abruptly during decreasing of the pressure ratio. The reverse process is not observed. When the cavity tone is produced in the pressure ratio range lower than 3.5, it is observed that the frequency of the cavity tone firstly appeared is not changed during decreasing of the pressure ratio. Less

近年来，下一代超音速客机正在研制中。超音速喷气机将用作这架飞机的推力。然而，众所周知，被称为尖叫音的非常强的声波被辐射。这种尖叫声是由反馈回路产生的，反馈回路由射流周围的下游对流相干旋涡结构和环境中的上游传播声波组成。超音速喷气式飞机的强噪声辐射将造成机场附近严重的噪声污染，并导致飞机的疲劳破坏。因此，本实验研究是为了阐明超声速喷流辐射噪声降低的可能性。本文研究了含空腔矩形喷管射流辐射的空腔音和尖厉音的声学特性。本年度，研究了从大气中喷出的超音速喷流所辐射的音调的声学特性， ...更多信息 对带空腔的圆形喷管进行了研究。实验结果表明：（1）有效地降低了频率高于腔音的尖厉音。(2)从带空腔喷嘴喷出的射流辐射的尖叫音的声压级（SPL）变得比从不带空腔喷嘴喷出的自由射流辐射的尖叫音的声压级最多低约30dB。空腔音的声压级比无空腔喷嘴自由射流辐射的尖叫音声压级最多低20dB左右。(3)当空腔长度为喷嘴直径的1.2倍时，出现11.5kHz和14.0kHz两种共振频率。当压比大于3.5的范围内出现11.5kHz的腔音频率时，随着压比的下降，频率突然变为14.0kHz。没有观察到相反的过程。当在低于3.5的压力比范围内产生腔音时，观察到在压力比减小期间，最初出现的腔音的频率不改变。少

项目成果

Y.Umeda and R.Ishii: "Oscillation modes of supersonic multijets" J.Acoustical Soc.America. 101. 3353-3360 (1997)

Y.Umeda 和 R.Ishii：“超音速多喷嘴的振荡模式”J.Acoustical Soc.America。

Y.Umeda: "Acoustical Characteristics of the noise radiated from supersonic multi-jets" Proc.16th International Cong.on Acoustics and 135th Meeting Acoust.Soc.America(Seattle, Wa.), Vol.4aPAc15. 1967-1968 (1998)

Y.Umeda：“超音速多喷嘴辐射噪声的声学特性”Proc.16th International Cong.on Acoustics and 135th Meeting Acoust.Soc.America（华盛顿州西雅图），Vol.4aPAc15。

Y.Umeda,R.Ishii: "Acoustical characteristics of the noise radiated from supersonic multi-jets" Proc.16th international congress on Acoustics and 135th Meeting Acoust.Soc.America(Seattle.Wa.). 4aPAc15. 1967-1968 (1998)

Y.Umeda、R.Ishii：“超音速多喷嘴辐射噪声的声学特性”，第 16 届国际声学大会和第 135 届美国声学协会会议（华盛顿州西雅图）。

Y.Umeda: "Osillation modes of supersonic multijets" J.Acoust.Soc.America. Vol.101. 3353-3360 (1997)

Y.Umeda：“超音速多喷嘴的振荡模式”J.Acoust.Soc.America。

Y.Umeda and R.Ishii: "Oscillation modes of supersonic multijets" J.Acoust.Soc.America. 101. 3353-3360 (1997)

Y.Umeda 和 R.Ishii：“超音速多喷嘴的振荡模式”J.Acoust.Soc.America。