The reactive attenuation of rectangular plenum chambers
The reactive attenuation of rectangular plenum chambers
复制标题
矩形静压室的反应衰减
DOI：
10.1016/0022-460x(92)90569-j
复制
发表时间：
1992
影响因子：
4.7
通讯作者：
J. Ih
中科院分区：
文献类型：
--
作者：
J. Ih
本文利用特征函数展开技术，导出了一个计算增压室声学性能的数学公式。该室被建模为活塞驱动的矩形刚性管，没有损失，并包含一个介质，否则在休息。通过叠加每个均匀波动活塞的三维速度势来获得腔室中的剩余声速势。所有的几何参数，如腔室和端口的大小，任意位置的入口/出口端口和端口的形状被考虑到在制定以及在端口腔室界面的区域不连续性处产生的声学高阶模式。利用所导出的2 × 2传递矩阵，可以表征通流、逆流、Helmholtz共振器和端进/侧出等任意形式的矩形腔室，并通过适当的声学模态序列截断，可以很容易地估算它们的插入或传输损耗。计算值与上述数值方法和经典平面波理论的预测值进行了比较，前者与本研究的结果吻合得很好。此外，还对90°和180°弯管进行了分析，计算结果与前人的实验结果吻合较好。导出的传递矩阵可以很容易地纳入任何现有的计算机程序，包括四极参数的基本模块，用于预测消声系统的声学性能。
A mathematical formulation for evaluating the acoustic performance of plenum chambers is derived by using the eigenfunction expansion technique. The chamber is modelled as a piston-driven rectangular rigid tube with no losses and containing a medium otherwise at rest. The residual acoustic velocity potential in the chamber is obtained by superposing the three-dimensional velocity potentials due to each of the uniformly fluctuating pistons. All the geometrical parameters such as the size of the chamber and ports, the arbitrary locations of inlet/outlet ports and the shapes of the ports are taken into consideration in the formulation as well as the acoustic higher order modes generated at the area discontinuities of port-chamber interfaces. By using the derived 2 × 2 transfer matrices, any type of reactive rectangular plenum chamber including the throughflow, flow-reversal, Helmholtz resonator and end-in/side-out configurations can be characterized, and their insertion or transmission losses can be estimated very easily through the appropriate truncation of acoustic modal series. Computed values are compared with those predicted by the foregoing numerical methods and by the classical plane wave theory, and the former agree very well with the results of the present study. In addition, 90° and 180° duct bends are analyzed and the results are in good agreement with previous experimental ones. The derived transfer matrices can be easily incorporated as basic modules in any existing computer programs incorporating four-pole parameters for predicting the acoustic performance of silencing systems.