Written in English
Thesis(M.Sc.) - Loughborough University of Technology 1971.
|Statement||by D.J. Snow.|
Presentation Mode Open Print Current View. Tools. Zoom Out. Zoom In. More Information Less Information Close Enter the password to open this PDF file: Cancel OK. File name: File size: Title: Author: Subject: . Attenuation of spiral modes in a circular and annular lined duct. 8. J. M. TYLER and T. G. SOFRIN Society of Automotive Enghteers Transacti Axial flow compressor noise studies. 9. L. S. WIRT Journal of the Acoustical Society of Amer Analysis, testing and design of lined ducts. ATTENUATION IN LINED Cited by: 6. In circular and annular lined ducts there exist modes of the sound field in both azimutal and radial directions. There are two distinct tasks to be solved for technical applications. Due to the coupling between the annular resonator and the constricted duct, the effective length of the annular resonator is greatly increased. To well understand the effect of higher order evanescent modes on sound transmission, a method based on the Green's function for a semi-infinite circular duct 20 P. E.
Circular and annular ducts are extensively treated in → Ch. s that chapter describes steps in such ducts with a multimode analysis, the present → Ch. K uses representations with a fundamental-mode analysis. Thus, in order to get some completeness in the collection of muffler elements in the present chapter, this section will present the transfer matrix method for an element which. High-order residual-based compact schemes for aerodynamics and aeroacoustics. Computers & Fluids, Vol. 61 Sound propagation attenuation in lined annular-variable area ducts using bulk-reacting liners. Applied Acoustics, Vol. 62, No. 7 Sound Attenuation in a Circular Duct of a Viscous Medium in the Absence of Mean Flow. Acoustic attenuation performance through a constricted duct is greatly improved by an annular resonator. A method based on the Green's function for a semi-infinite circular duct is proposed to calculate the transmission loss, where the velocity distributions are assumed to be uniform at the constriction inlet/outlets and at the inlet to the annular resonator. Sound attenuation in acoustically lined circular ducts in the presence of uniform flow and shear flow. S.-tt. Ko Journal of the Acoustical Society o/Amer Theoretical prediction of sound attenuation in acoustically lined annular ducts in .
Cremer's result, for the lowest order mode pair in the absence of flow, is generalized so that the optimum impedance and attenuation rate can now be obtained for any mode . Journal of Sound and Vibration () 22 (2), ACOUSTIC REFRACTION AND ATTENUATION IN CYLINDRICAL AND ANNULAR DUCTS P. N. SHANKAR Department of Aerospace Engineering, University of Maryland, College Park, Maryland , U.S.A. (Received 24 January ) Previous work has shown that refractive effects in sound propagation can be calculated correctly only . Modeling the higher-order modes in a duct is itself a numerically intensive procedure if fully coupled calculations are required. in a circular duct. Both point source and plane wave sources. H cm, fp, = , d/H= -~-, Cremer optimum. While the attenuation of the fundamental circumferential modes (i.e., m = 0) is independent of the channel width W, the attenuation of higher order circumferential modes m:A0 is strongly dependent on it .