Červenka Milan, Bednařík Michal, Groby Jean-Philippe
Faculty of Electrical Engineering, Czech Technical University in Prague, Technická 2, 16627 Prague 6, Czech Republic.
Laboratoire d'Acoustique de l'Université du Mans, LAUM - UMR CNRS 6613, Le Mans Université, Avenue Olivier Messiaen, 72085 Le Mans Cedex 9, France.
J Acoust Soc Am. 2019 Apr;145(4):2210. doi: 10.1121/1.5097167.
This paper reports a theoretical study of the sound propagation in a rectangular waveguide loaded by closely-spaced elongated side-branch resonators forming a simple low-frequency broadband reactive silencer. Semi-analytical calculations account for the evanescent modes both in the main waveguide and side-branch resonators and for the viscothermal losses in the silencer elements. Reasonable accuracy is maintained in the evaluation of transmission, reflection, and absorption coefficients, while the calculation time is reduced by a few hundred times in comparison with the finite element method. Therefore, the proposed method is particularly suitable for optimization procedure. The lengths of the individual equally spaced side-branch resonators are optimized by a heuristic evolutionary algorithm that maximizes the minimum transmission loss (TL) over a pre-defined frequency range. Numerical results indicate that the minimum TL of the optimized silencers is reduced due to the destructive effect of the evanescent coupling from the resonators of the nearest side-branches. In the opposite, the TL increases linearly with the number of the side-branch resonators.
本文报道了对一种矩形波导中声传播的理论研究，该矩形波导由紧密排列的细长侧支谐振器加载，形成一个简单的低频宽带无源消声器。半解析计算考虑了主波导和侧支谐振器中的消逝模以及消声器元件中的粘热损耗。在评估传输、反射和吸收系数时保持了合理的精度，同时与有限元方法相比，计算时间减少了几百倍。因此，所提出的方法特别适用于优化过程。通过启发式进化算法对各个等间距侧支谐振器的长度进行优化，该算法在预定义的频率范围内最大化最小传输损耗（TL）。数值结果表明，由于最近侧支谐振器的消逝耦合的破坏作用，优化后的消声器的最小TL降低。相反，TL随侧支谐振器的数量线性增加。
