Journal of Sound and Vibration

Palleja-Cabre S., Tester B.J., Astley R.J

Acoustic liners have traditionally been used in ducted systems to attenuate noise and are an essential treatment in modern commercial aircraft engines. Over-Tip-Rotor (OTR) liners installed in the duct casing over the fan rotor tip have been shown to provide further noise reductions than when installed in the intake. This paper focuses on modelling ducted point sources close to an acoustic liner. It is found that the source proximity to the liner surface has a significant impact on the source power output. This work offers insight on the source modification effects beyond the conventional approach in the design of liners solely based on acoustic absorption.

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