A finite element model of sound propagation in flow duct with its application to linear optimization

A finite element model is presented for sound propagation in a flow duct with an acoustic liner, which incorporates the major practical effects of wall impedance, variable duct geometry and non-uniform flow. This model is applied to simulate the duct liner effect on reducing the noise of a real high-speed rotor. Both the distribution andreduction of the sound pressure inside the duct and the optimized liner impedance are obtained. The results show that the present model can be used for the design purpose of a duct liner in the practical engineering applications.