An inviscid, spatial time-domain numerical simulation is employed to compute acoustic wave propagation in a duct treated with an acoustic liner. The motivation is to assess the effects on sound attenuation of bias flow passed through the liner for application to noise suppression in jet engine nacelles. Physically, the Iiner is composed of porous sheets with backing air cavities. The mathematical model Iumps the sheets' presence into a continuous empirical source term which modifies the right-hand side of the momentum equations. This source term specifies the time-domain characteristics of the frequency-domain resistance and reactance of the liner's component sheets. Nonlinear behavior of the liner sheets at high sound pressure levels is included in the form of the source term. The source term constants are empirically matched to frequency-domain impedance data via a one-dimensional numerical impedance tube simulation. The resulting liner model is then incorporated into a two-dimensional Euler solver and used for simulations of a realistic duct configuration. Sound pressure Ievels and axially transmitted power are computed to assess the attenuation effects of various magnitudes of bias flow. Simulation results are compared to available experimental data from a geometrically similar lined duct.
Time-domain simulation of acoustic propagation in a lined duct
Die zeitabhängige numerische Simulation der Schallausbreitung in einem ausgekleideten Rohr
Applied Acoustics ; 62 , 9 ; 1049-1068
2001
20 Seiten, 9 Bilder, 2 Tabellen, 15 Quellen
Article (Journal)
English
Time-Domain Simulation of Nonlinear Acoustic Propagation in a Lined Duct
British Library Conference Proceedings | 2008
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