Theoretical, numerical and experimental results are presented on the reactive and dissipative properties of backed or unbacked multilayer partitions made up of macro- or micro-perforated rigid panels in linear regime. The objective is to provide an enhanced multi-modal (EMM) formulation that accounts for high-order modes within the panel holes as well as visco-thermal boundary layers (VTBLs) over the panel surfaces while being computationally more efficient than the finite element method (FEM). The proposed model accounts for oblique incidence and finite-sized panel vibrations. Validation cases show that the EMM well captures the visco-thermal dissipation modelled by FEM on rigidly-backed macro- and micro-perforates. It also well correlates with a number of effective impedance models provided suitable end-corrections are used. The measured acoustical properties of unbacked multi-layer partitions are accurately predicted by the EMM, well beyond the validity range of the effective models. The thickness-to-hole diameter aspect ratio is found to be a key parameter that determines the relative contribution of the in-hole radial modes and VTBLs to the partition dissipation properties. For aspect ratios greater than unity where micro-perforates normally are operated, the dissipation is dominated by the high-order in-hole modes. Otherwise, both the VTBLs and in-hole modes contribute to the transmission and dissipation. The VTBLs also dominate the reactive and dissipative properties of acoustic fishnets embedding small air gaps comparable to the VTBL thickness. Despite the constant hole pitch limitation, the EMM appears to be well-suited for the optimisation study of the dissipative and reactive properties of backed or unbacked multi-layer partitions.

理论，数值和实验结果在线性状态下由宏观或微观穿孔的刚性面板组成的有背或无背多层隔板的反应和耗散性能方面都给出了。目的是提供一种增强的多模态（EMM）公式，以解决面板孔内的高阶模态以及面板表面上的粘热边界层（VTBL），同时在计算上比有限元方法更有效（FEM）。所提出的模型考虑了斜入射和有限尺寸的面板振动。验证案例表明，EMM能够很好地捕获FEM在刚性支撑的宏观和微观穿孔上模拟的粘热耗散。如果使用了适当的端部校正，它也可以与许多有效的阻抗模型很好地相关。EMM可以准确地预测无衬砌的多层隔断的声学性能，远超出有效模型的有效范围。发现厚度与孔径的纵横比是确定井内径向模式和VTBL对分隔耗散性能的相对贡献的关键参数。对于正常操作微穿孔的宽高比大于1的纵横比，耗散主要由高阶孔内模式控制。否则，VTBL和孔内模式都会影响传输和耗散。VTBLs还占据了声鱼网的反应性和耗散特性，并嵌入了与VTBL厚度相当的小气隙。尽管有恒定的孔距限制，