Sound wave scattering in a flow duct with azimuthally non-uniform liners. (2nd February 2018)

• Record Type: Journal Article
• Authors: Jiang, Hanbo; Lau, Alex Siu Hong; Huang, Xun
• Is Part Of: Journal of fluid mechanics. Volume 839(2018)
• Page Start: 644
• Page End: 662
• Publication Date: 2018-02-02
• Subjects: aeroacoustics, -- noise control, -- waves in random media; Fluid mechanics -- Periodicals; 532.005
• DOI: 10.1017/jfm.2018.44
• Languages: English
• ISSNs: 0022-1120

Abstract

Abstract : Novel acoustic liner designs often incorporate new materials with non-uniform impedance distributions. Therefore, new methods are required for their modelling and analysis. In this paper, a theoretical model is developed to investigate the scattering of sound waves from an axially symmetrical flow duct with a semi-infinite, azimuthally non-uniform acoustic lining on the duct wall. More specifically, the incorporation of Fourier series expansions into the Wiener–Hopf method leads to an analytical model with a matrix kernel, which is further factorised by using the pole-removal method to obtain a closed-form solution. A new mathematical method is developed to solve the residues associated with the pole-removal technique. The proposed model has been verified and validated by comparing with corresponding computational results. In addition to shedding light on the possible physical effect of azimuthally non-uniform liners along with an axial hard–soft interface, the current model enhances the theoretical modelling capability for a complicated set-up of practical importance, and can be used to investigate new liner designs for passive noise control in flow ducts.