三弹性圆柱壳体多重耦合声辐射计算方法

为研究多圆柱壳组合结构的声辐射特性,采用模态叠加法建立了3个并排无限长弹性圆柱壳的振动声散射耦合物理模型,充分考虑了三圆柱壳的表面振动与散射声场的耦合,其中散射声场可分解为各圆柱壳刚性散射声场和弹性辐射声场的叠加,数学上将各壳间的声场耦合关系通过柱函数加法公式描述。利用该物理模型,分析了多重散射对稳态声场求解结果的影响,比较了三圆柱壳耦合系统与单个圆柱壳系统的辐射声场指向性、声压级及辐射声功率级的差异及其产生机理,结果表明:结构弹性耦合声辐射不仅在低频对总声场有显著影响,在高频范围也不可忽略;另外,针对本文设定参数的组合圆柱壳,在150 Hz以上频段,两旁圆柱壳对中间圆柱壳在正横方位产生了声辐射遮蔽效应,垂直方位则体现声泄漏作用。本文建立的方法可推广到三维空间任意多壳结构的声振耦合建模。

Coupling sound radiation characteristics of 3 side-by-side flexible cylindrical shells

To investigate the coupling sound radiation characteristics of 3 side-by-side flexible cylindrical shells, a mathematical physical model is established which involves the sound radiation and scattering of every cylindrical shell. In this model, Mode-Expansion method is adopted to solve the coupling equations, Hankel Function Transferring is used to describe the coupling of vibration and sound of 3 shells. Then, the effect of multi-rescattering of the shells is verified, and the difference between the sound field distribution of 3 combined cylindrical shells and the single shell is studied, and also the sound pressure level and the sound power level. The results show that the elastic interaction of the shells affects not only the low-frequency but also the high-frequency sound field; and the existence of the lateral shells can lead to the sound-shielding in the abeam direction, yet the sound enhancing of the vertical direction.