Taktak Mohamed, Ville Jean Michel, Haddar Mohamed, Gabard Gwénaël, Foucart Felix
Laboratoire Roberval UMR UTC-CNRS 6253, Université de Technologie de Compiègne, BP 20529, F60205 Compiègne Cedex, France.
J Acoust Soc Am. 2010 Jun;127(6):3548-59. doi: 10.1121/1.3365250.
An indirect technique for educing the homogenized acoustic impedance of a liner mounted on the wall of a barrel is presented. It is based on measurements and computational simulations of the multimodal scattering matrix of this lined duct. Measurements are performed with a multisource method and the use of an anechoic duct termination. The numerical computation of the scattering matrix relies on a finite element model, and assume that the duct is axisymmetric and uniformly covered by a locally reacting material. The impedance is educed by minimizing the difference between the theoretical and experimental acoustic power dissipations, which are deduced from the scattering matrix. The source is an incoming pressure field generated at one end of the duct only and composed of all cut-on modes. This technique was tested on a cylindrical barrel whose wall was partially lined with a realistic, locally reacting material made of honeycomb cells and a perforated facing sheet. Results for the acoustic impedance are compared with those deduced from semiempirical models and the experimental two microphone method. The best agreement with the indirect method is found with the semiempirical impedance results when the difference between the acoustic power dissipated by the actual lined barrel and the reference barrel is chosen as the cost function of the minimizing procedure.
提出了一种用于推导安装在桶壁上的衬里的均匀化声阻抗的间接技术。它基于对该衬里管道多模散射矩阵的测量和计算模拟。测量采用多源方法并使用消声管道终端进行。散射矩阵的数值计算依赖于有限元模型，并假设管道是轴对称的且被局部反应材料均匀覆盖。通过最小化从散射矩阵推导得到的理论和实验声功率耗散之间的差异来推导阻抗。声源是仅在管道一端产生的入射压力场，由所有截止模式组成。该技术在一个圆柱形桶上进行了测试，该桶的壁部分衬有由蜂窝单元和穿孔面板制成的实际局部反应材料。将声阻抗结果与从半经验模型和实验双传声器方法推导得到的结果进行了比较。当选择实际衬里桶和参考桶耗散的声功率之差作为最小化过程的代价函数时，半经验阻抗结果与间接方法的一致性最佳。
