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Numerical study of pore-scale flow and noise of an open cell metal foam

Numerical study of pore-scale flow and noise of an open cell metal foam
Numerical study of pore-scale flow and noise of an open cell metal foam

This paper studies numerically the three-dimensional pore-scale flow inside a single cell structure of an open cell metal foam and its aeroacoustic features. Since the Reynolds number based on the pore diameter is very low, the Navier–Stokes equations are solved directly to simulate the unsteady pore-scale flow. The permeability and pressure drop obtained from numerical simulations are compared with existing reference results. Numerical results reveal that the flow drag of the pore-scale structure is dominated by the pressure drag which is mainly caused by the flow separation, while the friction drag is much smaller than the pressure drag despite a very high surface area–volume ratio of the metal foam. The unsteady flow separation contributes primarily to the pressure drag and causes the self-noise of the metal foam, therefore suppressing the unsteady flow separation, e.g., by optimizing the cell structure of the metal foam, would reduce the drag and aerodynamic noise. The aeroacoustic features, such as noise sources, spectra and the directivity pattern, are investigated, and the results reveal a high correlation between the noise generation and the flow separation. The direction of the maximum sound pressure for the studied cell is parallel to the flow, which is different to flow separation from a cylinder where the direction of maximum radiation is perpendicular to the flow.

Aerodynamic noise, Flow loss, Flow separation, Open-cell metal foam, Pore-scale flow
1270-9638
185-198
Xu, Chen
b53e92d4-e474-420b-a662-4af9a1c8750b
Mao, Yijun
3012974a-d258-4a40-8461-b4c41b9cf85c
Hu, Zhiwei
dd985844-1e6b-44ba-9e1d-fa57c6c88d65
Xu, Chen
b53e92d4-e474-420b-a662-4af9a1c8750b
Mao, Yijun
3012974a-d258-4a40-8461-b4c41b9cf85c
Hu, Zhiwei
dd985844-1e6b-44ba-9e1d-fa57c6c88d65

Xu, Chen, Mao, Yijun and Hu, Zhiwei (2018) Numerical study of pore-scale flow and noise of an open cell metal foam. Aerospace Science and Technology, 82-83, 185-198. (doi:10.1016/j.ast.2018.09.002).

Record type: Article

Abstract

This paper studies numerically the three-dimensional pore-scale flow inside a single cell structure of an open cell metal foam and its aeroacoustic features. Since the Reynolds number based on the pore diameter is very low, the Navier–Stokes equations are solved directly to simulate the unsteady pore-scale flow. The permeability and pressure drop obtained from numerical simulations are compared with existing reference results. Numerical results reveal that the flow drag of the pore-scale structure is dominated by the pressure drag which is mainly caused by the flow separation, while the friction drag is much smaller than the pressure drag despite a very high surface area–volume ratio of the metal foam. The unsteady flow separation contributes primarily to the pressure drag and causes the self-noise of the metal foam, therefore suppressing the unsteady flow separation, e.g., by optimizing the cell structure of the metal foam, would reduce the drag and aerodynamic noise. The aeroacoustic features, such as noise sources, spectra and the directivity pattern, are investigated, and the results reveal a high correlation between the noise generation and the flow separation. The direction of the maximum sound pressure for the studied cell is parallel to the flow, which is different to flow separation from a cylinder where the direction of maximum radiation is perpendicular to the flow.

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FinalSubmission 201808 - Accepted Manuscript
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More information

Accepted/In Press date: 2 September 2018
e-pub ahead of print date: 5 September 2018
Published date: November 2018
Keywords: Aerodynamic noise, Flow loss, Flow separation, Open-cell metal foam, Pore-scale flow

Identifiers

Local EPrints ID: 426901
URI: http://eprints.soton.ac.uk/id/eprint/426901
ISSN: 1270-9638
PURE UUID: f4d552e2-94cb-4fa3-a1cd-34b5df614f11

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Date deposited: 14 Dec 2018 17:30
Last modified: 07 Oct 2020 06:34

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