High-frequency aeroacoustic source mechanisms of a structured porous coated cylinder

Elias J.G. Arcondoulis, Riccardo Zamponi, İris Alagöz, Francesco Avallone, Chaitanya Paruchuri

Research output: Chapter in Book/Conference proceedings/Edited volumeConference contributionScientificpeer-review

Abstract

The application of a porous coating to a bluff body, such as a cylinder, is an efficient passive flow control method and has applications in wind, aerospace, and civil engineering. Despite its effectiveness in reducing vortex-shedding processes and the associated noise-generating mechanisms, there exists a trade-off in terms of the generation of higher frequency noise. Such acoustic emissions can be irritating to the human ear and thereby diminish some of the benefits of porous media as a form of passive flow and noise control. To date, explanations of the mechanisms responsible for high-frequency noise generation of a porous coated cylinder (PCC) are qualitative, and there is no clear consensus. In this paper, it is hypothesized that the high-frequency noise is caused by local vortex shedding around the structural members of the pores that comprise the porous media on the cylinder windward side. To investigate this claim, a mathematical model is derived based on the premise that a porous cylinder potential flow model accurately captures the total velocity at the outer diameter of a PCC. The acoustic shedding frequencies are assumed to be related to the Strouhal number relationship, and the acoustic intensity is assumed to be consistent with Curle’s theory, where acoustic intensity scales with the sixth power of flow velocity and the characteristic length squared. A lattice-Boltzmann method simulation of a simplified structured PCC, following a previously published design, is used to test the analytical model, yielding excellent agreement with the mathematical model in terms of acoustic intensity and frequency range.

Original languageEnglish
Title of host publication30th AIAA/CEAS Aeroacoustics Conference, 2024
PublisherAmerican Institute of Aeronautics and Astronautics Inc. (AIAA)
Number of pages22
ISBN (Print)9781624107207
DOIs
Publication statusPublished - 2024
Event30th AIAA/CEAS Aeroacoustics Conference, 2024 - Rome, Italy
Duration: 4 Jun 20237 Jun 2023

Publication series

Name30th AIAA/CEAS Aeroacoustics Conference, 2024

Conference

Conference30th AIAA/CEAS Aeroacoustics Conference, 2024
Country/TerritoryItaly
CityRome
Period4/06/237/06/23

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