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冲击射流噪声研究可为减轻垂直起降型飞机的声致疲劳提供思路。用快速Fourier变换得到了不同形状冲击面条件下冲击射流的远场噪声,并分析了噪声频谱。结果表明:对于凹、凸、平三种形状的冲击面,当冲击距离较小时,冲击单音主导了离散频率噪声;冲击单音最强音的频率随压比增大呈现频级阶越的现象;射流噪声总声压级随压比成类似对数增长的关系,当喷嘴压比大于2.5后,总声压级随压比的增长趋于缓慢;对于冲击面为凹面的冲击射流,远场噪声总声压级对喷嘴位置改变非常敏感。
Impinging jet noise research can provide ideas for alleviating acoustic fatigue caused by vertical takeoff and landing aircraft. The far-field noise of impinging jets under different shapes of impact surface is obtained by fast Fourier transform, and the noise spectrum is analyzed. The results show that for the impact surface of concave, convex and flat shape, when the impact distance is small, the impact of single tone dominates the discrete frequency noise; the strongest tone of the impact tone increases with the increase of pressure ratio, Phenomenon; jet noise total sound pressure level with a similar logarithmic growth pressure ratio, when the nozzle pressure ratio is greater than 2.5, the total sound pressure level increases with the pressure ratio tends to be slow; for the impact surface is concave jet impact, far Field Noise The total sound pressure level is very sensitive to nozzle position changes.