On the length scale and Strouhal numbers for sound transmission across coupled duct cavities at low Mach number

Tang, S. K.; Tang, Yijia

Abstract

The sound transmission across two coupled cavities along a rectangular duct in the presence of a low Mach number flow is examined experimentally in the present study. An effort is also made for a deeper understanding of how the flow, excitation sound frequency, and excitation level influence the sound transmission loss. The results confirm that the high sound transmission loss across the cavities is associated with the strong out-of-phase pressure fluctuations within the cavities. The sound transmission loss deteriorates significantly once the flow speed exceeds a threshold value. A different length scale is proposed. This length scale, together with the threshold flow speed and the peak sound transmission loss frequency, gives a Strouhal number, which is basically independent of the cavity offset for a fixed cavity length. The present finding extends the previous effort of the authors, enabling the prediction of the flow speed limit and operating frequency of the coupled cavities for duct silencing at a low Mach number.

Citation

Tang, S. K., & Tang, Y. (2021). On the length scale and Strouhal numbers for sound transmission across coupled duct cavities at low Mach number. The Journal of the Acoustical Society of America, 150(6), 4232-4243. https://doi.org/10.1121/10.0008950

• Journal Article Type: Article
• Acceptance Date: Nov 15, 2021
• Online Publication Date: Dec 9, 2021
• Publication Date: 2021-12
• 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: 150
• Issue: 6
• Pages: 4232-4243
• DOI: https://doi.org/10.1121/10.0008950
• Public URL: https://hull-repository.worktribe.com/output/4015633