Toyoda Masahiro, Motooka Junya
Department of Architecture, Faculty of Environmental and Urban Engineering, Kansai University, 3-3-35, Yamate-cho, Suita-shi, Osaka, 564-8680, Japan.
J Acoust Soc Am. 2018 May;143(5):2870. doi: 10.1121/1.5037708.
Permeable thin materials can play a role similar to porous absorbents, providing high sound absorption at mid- and high-frequencies. In addition, since they can be made from various materials such as cotton, chemical fibers, and metal fibers, they can be hygienic, durable, and easy to recycle. Their absorption characteristics are often discussed with analytical approaches, and a few studies have even applied the boundary element method and the finite element method to predict the practical effects of permeable thin absorbers. However, to the best of the authors' knowledge, the finite-difference time-domain (FDTD) method has yet to be used. Herein a formulation to deal with a permeable thin absorber as a permeable boundary in the FDTD method is proposed and the stability conditions for a permeable boundary are derived considering the state transition equations. The proposed formulation is validated by comparing the numerical and analytical results, which agree well.
可渗透薄材料可起到类似于多孔吸收剂的作用，在中高频提供高吸声性能。此外，由于它们可以由各种材料制成，如棉花、化学纤维和金属纤维，因此它们可以卫生、耐用且易于回收。人们经常用分析方法讨论它们的吸收特性，甚至有一些研究应用边界元法和有限元法来预测可渗透薄吸声器的实际效果。然而，据作者所知，时域有限差分（FDTD）方法尚未被使用。在此，提出了一种在FDTD方法中将可渗透薄吸声器作为可渗透边界处理的公式，并考虑状态转移方程推导了可渗透边界的稳定性条件。通过比较数值结果和分析结果对所提出的公式进行了验证，两者吻合良好。
