Narrow sidebranch arrays for low frequency duct noise control

Shiu Keung Tang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

31 Citations (Scopus)


The present study investigates the sound transmission loss across a section of an infinitely long duct where one or more narrow sidebranch tubes are installed flushed with the duct wall. The finite-element method is used to compute the wave propagation characteristics, and a simplified theoretical analysis is carried out at the same time to explain the wave mechanism at frequencies of high sound reduction. Results show that the high sound transmission loss at a particular frequency is due to the concerted actions of three consecutive sidebranch tubes with the most upstream one in the resonant state. The expansion chamber effect of the setup also plays a role in enhancing sound attenuation at non-resonance frequencies. Broadband performance of the device can be greatly enhanced by appropriate arrangements of tube lengths and/or by coupling arrays on the two sides of the duct.
Original languageEnglish
Pages (from-to)3086-3097
Number of pages12
JournalJournal of the Acoustical Society of America
Issue number5
Publication statusPublished - 1 Nov 2012

ASJC Scopus subject areas

  • Acoustics and Ultrasonics
  • Arts and Humanities (miscellaneous)

Cite this