This investigation uses methods based on the Pridmore-Brown and convected Helmholtz equations to study the acoustic behavior of a single-layer, conventional liner fabricated by DLR, German Aerospace Center and tested in the NASA Langley Grazing Flow Impedance Tube. Two key assumptions are explored in this investigation. First, a comparison of results achieved with uniform-flow and shear-flow impedance eduction methods is considered. Second, an approach based on the Prony method is used to extend these methods from single-mode to multimode implementations. In addition, a detailed study into the effects of harmonic distortion on the educed impedance is performed, and the results are used to develop guidelines regarding acceptable levels of harmonic distortion.
Effects of Mean Flow Assumption and Harmonic Distortion on Impedance Eduction Methods
AIAA Journal ; 53 , 6 ; 1503-1514
2014-10-21
12 pages
Article (Journal)
Electronic Resource
English
Effects of Mean Flow Assumption and Harmonic Distortion on Impedance Eduction Methods
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