This paper presents the contribution from the German Aerospace Center (DLR) to the first liner benchmark challenge under the framework of the International Forum for Aviation Research (IFAR). Therefore, two sets of acoustically damping wall treatments, called ‘liner samples’, have been produced by additive manufacturing based on the design data provided by NASA coordinating this benchmark. These liner samples have been integrated and acoustically characterized in the liner flow test facility DUCT-R at DLR Berlin as well as in the liner flow test facility GFIT at NASA Langley. Besides the dissipation coefficients and the axial pressure profiles, the liner wall impedance was educed by first determining the axial wave numbers and then applying a straightforward method based on the one-dimensional Convected Helmholtz Equation. Finally, the comparison of the liner impedance values to the NASA results show a fairly good agreement.

本文介绍了德国航空航天中心 (DLR) 在国际航空研究论坛 (IFAR) 框架下对首个班轮基准挑战的贡献。因此，根据 NASA 提供的设计数据，通过增材制造生产了两组声阻尼墙处理，称为“衬垫样品”。这些衬管样品已在 DLR Berlin 的衬管流量测试设备 DUCT-R 以及 NASA Langley 的衬管流量测试设备 GFIT 中进行集成和声学表征。除了耗散系数和轴向压力分布之外，通过首先确定轴向波数然后应用基于一维对流亥姆霍兹方程的简单方法来推导出衬管壁阻抗。最后，