What is it about?
This work studies the effect of ducts, pipes and tubes on the sound produced from noise generating components or sources. This work is motivated by a need to better understand the sound produced from aircraft fans and rotors, which are often ducted to enhance their performance. This work allows for a better understanding of the noise from ducted sources which, in turn, may be used to reduce the radiated noise by for example using duct liners. This new understanding is used to explore the effects of the location of the sound source inside the duct and this is compared to an un-ducted open source to establish when the effect of the duct is small and under what circumstances noise reduction can be achieved.
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Why is it important?
Aircraft noise is a significant nuisance in todays society. With many communities located along flight paths frequently disturbed by loud and disruptive noises. This work aims to develop better modelling techniques for ducted noise generating components which intern can be used to reduce the noise from aircraft engines.
Perspectives
This work is a fundamental study intended to answer the questions such as "when is a duct not a duct" and "what is the effect of ducts on noise generating components". Although the mathematics are relatively complicated, this work focuses on the results, mostly focusing on directivity plots, noise against angle. The location of the source inside the duct is the main focus of the study where it is shown the source location can have a dominating effect on the sound radiated, implying simply moving the source in the duct could have a noise reducing effect.
Ben Baddour
University of Southampton
Read the Original
This page is a summary of: Open-to-Ducted Transfer Function for Point Dipole Sources, June 2022, American Institute of Aeronautics and Astronautics (AIAA),
DOI: 10.2514/6.2022-3083.
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