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在高速风洞中对空腔流场气动声学特性进行了试验研究,对空腔后壁进行倒角,以降低气流在该处的撞击强度,从而达到抑制空腔流场气动噪声的目的。试验马赫数(Ma)为0.6~1.2,空腔长深比(L/D)为4.1、4.7。试验结果表明:亚跨声速范围内,随马赫数增大,开式空腔流场气动声学环境恶劣程度加剧,最大总声压级高达170dB以上,声压频谱曲线上存在多个不同模态的单调声;后壁倒角后,腔底总声压级强度明显降低,且其降低程度随马赫数增大愈趋明显,最大可降低近7dB,空腔后壁上主噪声源附近总声压级强度可降低约1dB,声压频谱曲线上的能量峰值明显减弱。
In high-speed wind tunnel, the aerodynamic and acoustic characteristics of the cavity flow field were studied. The back wall of the cavity was chamfered to reduce the impact strength of the airflow at the place, so as to suppress the aerodynamic noise in the cavity flow field. The test Mach number is 0.6 to 1.2 and the cavity depth to depth ratio (L / D) is 4.1 and 4.7. The experimental results show that with the increase of Mach number, the aerodynamic acoustics environment of open cavity is aggravated by the increase of Mach number, the maximum total sound pressure level is over 170 dB, and there are many different modes of sound pressure spectrum Monotonous sound; rear wall chamfering, the cavity bottom sound pressure level intensity decreased significantly, and the degree of reduction increases with the Mach number becomes more apparent, the maximum can be reduced by nearly 7dB, the main cavity near the noise source of the total noise The level strength can be reduced by about 1 dB, and the energy peak on the sound pressure spectrum curve is significantly weakened.