其他摘要：This paper presents a mathematical model to simulate the sound radiation from a moving boundary of a lined circular duct in the presence of a convective axial flow. The model is based on finding a new closed form solution for the Green’s functions of the convected wave equation inside a soft wall duct, using the eigenfunctions method. Using the Divergence Theorem, this closed form solution allows to find expressions for the sound field generated by a rectangular shaped piston source with uniform velocity. This formulation can be applied to model discontinuities in acoustic liners for turban engines such as embedded actuators used in active noise control, the scattering effects of liner splices near the fan and so forth. By properly selecting the piston velocity or strength, the different discontinuities in the liner can be modeled. An example consisting of a circumferential array of rigid patches mounted on the wall of the lined duct is described.
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