基于可变形空腔的起落架舱体噪声抑制研究

Noise suppression of landing gear cabin based on deformable cavity

提出了一种基于可变形空腔的起落架舱体结构,通过机械装置调节舱体底板及后壁倾斜角度,不需要额外增加舱体体积,使用声学有限元法探讨了该结构在低马赫数下的噪声抑制效果。研究发现:随着舱体后壁倾斜角度的增大,舱体内部及外部的噪声明显减小,同时模态频率逐渐增大,有助于避免舱体结构发生共振破坏;舱体后壁倾斜一个较小的角度就能有效地改善内部的声反射环境,进而抑制舱体内部的高频模态噪声、总声压级。当后壁倾斜角度大于某个临界值时,继续增大倾斜角度对于舱体内部高频模态噪声以及总声压级的抑制效果不再明显,在当前的仿真条件下,舱体后壁最佳倾斜角度范围为10°~16°。

Here,a landing gear cabin structure based on deformable cavity was proposed.Inclination angles of cabin bottom plate and rear wall were adjusted using mechanical device without additional cabin volume.The noise suppression effect of the cabin structure at low Mach number was discussed with the acoustic finite element method.It was shown that noise inside and outside the cabin decreases obviously with increase in inclination angle of the cabin rear wall,meanwhile the cabin’s modal frequencies increase gradually to avoid resonance failure of the cabin structure;a smaller inclination of cabin rear wall can effectively improve internal acoustic reflection environment,and then suppress high-frequency modal noise and total sound pressure level inside cabin;when inclination angle of cabin rear wall is larger than a certain critical value,the suppression effect of increasing inclination angle on high-frequency modal noise and total sound pressure level inside cabin is no longer obvious;under current simulation conditions,the optimal inclination angle range of cabin rear wall is 10°-16°.