椭圆空腔型水下吸声覆盖层抗探测能力研究

Research on anti-detection ability of elliptical cavity underwater sound-absorbing coating

摘要:

内嵌多层椭圆空腔的吸声覆盖层中相邻空腔和钢背衬可组成多个Fabry-Pérot ( F-P ) 共振结构，显著降低其声学可探测性。为实现高性能声学隐身结构，通过改变空腔形状及方位角引起F-P共振模态变化，增强抗声波探测性能。本研究建立了内嵌三层椭圆形空腔的吸声覆盖层的解析与数值模型，系统研究了椭圆空腔的排布、尺寸、长宽比和方位角对覆盖层抗探测性能的影响，通过解析结果和数值结果的对比验证了模型的正确性。研究结果表明：固定空腔面积不变，增长所有椭圆空腔长轴会引起吸收峰频率向低频偏移和吸声系数减小；固定长轴不变，缩短短轴能够调控两个相邻吸收峰融合为宽频的高效吸收峰；改变椭圆方位角仅会导致F-P共振模态改变，并不影响吸声结果。因此，合理改变椭圆空腔的长宽比能够增强吸声覆盖层的声波抗探测能力。

Abstract:

Multiple Fabry-Pérot ( F-P ) resonance structures can be formed by the adjacent cavity and the steel backing in the sound absorption coating embedded with multi-layer elliptical cavity, which significantly reduces its acoustic detectability. In order to achieve high-performance acoustic stealth structure, the F-P resonance mode is changed by changing the cavity shape and azimuth angle, and the anti-acoustic detection performance is enhanced. In this study, the analytical and numerical models of the sound absorption covering layer with three-layer elliptical cavity are established. The effects of the arrangement, size, aspect ratio and azimuth angle of the elliptical cavity on the anti-detection performance of the covering layer are systematically studied. The correctness of the model is verified by the comparison between the analytical results and the numerical results. The results show that when the cavity area is fixed, increasing the long axis of all elliptical cavities will cause the absorption peak frequency to shift to low frequency and the sound absorption coefficient to decrease. Fixed the long axis unchanged, shortening the short axis can regulate the fusion of two adjacent absorption peaks into a broadband high-efficiency absorption peak ; changing the elliptical azimuth only leads to the change of F-P resonance mode, and does not affect the sound absorption results. Therefore, reasonably changing the aspect ratio of the elliptical cavity can enhance the acoustic anti-detection ability of the overburden.