Analysis of the oblique incidence of periodic structures in a sound field by the finite-difference time-domain method. (October 2020)

• Record Type: Journal Article
• Authors: Takemura, Miho; Toyoda, Masahiro
• Is Part Of: Applied acoustics. Volume 167(2020)
• Publication Date: 2020-10
• Subjects: FDTD method -- Periodic structure -- Oblique incidence of plane wave -- Transmission loss; Acoustical engineering -- Periodicals; Periodicals; 620.2
• DOI: 10.1016/j.apacoust.2020.107357
• Languages: English
• ISSNs: 0003-682X

Abstract

Abstract: A method to analyze the acoustic characteristics of periodic structures is investigated. When a continuous boundary condition is introduced, the field in which a plane wave is normally incident on the periodic structure can be easily analyzed by the finite-difference time-domain (FDTD) method. However, when a plane wave source is obliquely incident, field mapping with auxiliary variables is necessary to remove the phase shift between unit cells. Here, a technique originally proposed for an electromagnetic field is applied to a sound field. The effects of the geometric parameters of the periodic structures on the sound pressure distribution and transmission loss in the mapped sound field are shown. This technique is validated by comparing the results with those in a field solved with the classical FDTD scheme. The dispersion relation and the stability condition for the time interval of the FDTD method for each incident angle of the plane wave in the mapped field are studied.