Liu Daipei, Havránek Zdeněk, Marburg Steffen, Peters Herwig, Kessissoglou Nicole
School of Mechanical and Manufacturing Engineering, The University of New South Wales, Sydney, New South Wales 2052, Australia.
CEITEC-Central European Institute of Technology, Brno University of Technology, Purkynova 656/123, 612 00 Brno, Czech Republic.
J Acoust Soc Am. 2017 Jul;142(1):117. doi: 10.1121/1.4990374.
Non-negative intensity (NNI) is an approach to identify the surface areas of a structure that contribute to sound power. NNI is evaluated in terms of the acoustic impedance matrix obtained directly at the structural surface and as such can only identify surface contributions to sound power at a far-field receiver surface that fully circumscribes the structure. In contrast, back-calculated NNI is evaluated in terms of the acoustic impedance matrix obtained at a far-field receiver surface, and hence can identify surface contributions to sound power at a far-field receiver surface that does not fully circumscribe the structure. In this work, NNI and acoustic intensity obtained numerically using the boundary element method and experimentally from near-field acoustic holography measurements are compared for different modes. Back-calculated NNI evaluated for full and partial receiver surfaces is also compared with acoustic intensity for the different modes. Results for back-calculated NNI show that different regions on the plate surface contribute sound to different receiver locations.
非负强度（NNI）是一种识别对声功率有贡献的结构表面积的方法。NNI是根据直接在结构表面获得的声阻抗矩阵来评估的，因此只能识别在完全包围该结构的远场接收器表面上对声功率的表面贡献。相比之下，反向计算的NNI是根据在远场接收器表面获得的声阻抗矩阵来评估的，因此可以识别在未完全包围该结构的远场接收器表面上对声功率的表面贡献。在这项工作中，针对不同模式，比较了使用边界元法数值获得的NNI和声强以及通过近场声全息测量实验获得的NNI和声强。还将针对完整和部分接收器表面评估的反向计算的NNI与不同模式的声强进行了比较。反向计算的NNI结果表明，板表面上的不同区域对不同的接收器位置贡献声音。
