A time-domain method for the prediction of sound attenuation in lined ducts

This paper describes the development and application of a time-domain acous tic liner model which is suitable for the simulation of sound propagation a nd attenuation in lined ducts. The fluid Row within the duct domain is repr esented by the non-linear. unsteady Euler equations while the liner model c onsists of a resistive frequency-independent part and a reactive part which is obtained by solving the one-dimensional Euler equations within the line r cavity. Specialized boundary conditions are used for matching the 1D cavi ty Row and the 2D duct flow. The liner model has been formulated in order t o predict the sound attenuation with or without mean Row. as well as for li near or non-linear sound propagation. The model has been validated in the c ase of linear pure-tone and N-wave signals by checking against analytical F ormulations obtained via eigensolutions of the linearized inviscid Row equa tions. Very good agreement was obtained for both zero and subsonic mean flo ws. (C) 2001 Academic Press.