Simulation of acoustic liner performance in a grazing flow duct

Abstract

Acoustic liners are commonly used to reduce aircraft engine noise. The performance of acoustic liners can be tested in a grazing flow duct. In order to simulate the new extended-reaction liners which allow lateral acoustic propagation inside the liner, finite element methods have been used in the frequency domain computation. In this study, different liner core materials, including honeycomb and foam-metal, are simulated with uniform or varied material properties and geometries. Frequency responses of liners are studied with different materials under several flow conditions. An immersed-boundary, time-domain simulation is also implemented to simulate the broad-band behavior of the liners and to compare with the frequency-domain computation. Optimized material properties and liner arrangement for noise reduction will be investigated.