Sound transmission across a narrow sidebranch array duct muffler at low Mach number

Yu, H. M.; Tang, S. K.

Abstract

The sound transmission loss across a duct muffler in the form of a linear array of 11 narrow sidebranches is examined experimentally in the present study. The introduction of a low Mach number duct flow deteriorates the broadband acoustical performance of the muffler and strong sound transmission loss dips and sound amplifications are observed at high flow speeds. It is found that a stronger acoustic pressure magnitude inside the sidebranches improves the muffler's performance in the presence of the duct flow. A theoretical analysis using a 2-sidebranch array muffler is conducted and the results indicate the possibility of increasing the sound pressures inside the sidebranches by locating the shorter sidebranch upstream of the longer one. The results of further experiments validate the theoretical deduction. Results also confirm that the muffler with sidebranches arranged in the order of decreasing acoustic impedance magnitude has stronger resilience against aerodynamic disturbance and gives better performance when the upstream excitation level and the duct flow speed are fixed.

Citation

Yu, H. M., & Tang, S. K. (2020). Sound transmission across a narrow sidebranch array duct muffler at low Mach number. The Journal of the Acoustical Society of America, 148(3), 1692-1702. https://doi.org/10.1121/10.0001993

• Journal Article Type: Article
• Acceptance Date: Sep 2, 2020
• Online Publication Date: Sep 23, 2020
• Publication Date: Sep 1, 2020
• Deposit Date: Jul 11, 2022
• Publicly Available Date: Jul 27, 2022
• Journal: Journal of the Acoustical Society of America
• Print ISSN: 0001-4966
• Electronic ISSN: 1520-8524
• Publisher: Acoustical Society of America
• Peer Reviewed: Peer Reviewed
• Volume: 148
• Issue: 3
• Pages: 1692-1702
• DOI: https://doi.org/10.1121/10.0001993
• Public URL: https://hull-repository.worktribe.com/output/4015663