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Characterisation of sheet cavity noise of a hydrofoil using the Ffowcs Williams-Hawkings acoustic analogy

Characterisation of sheet cavity noise of a hydrofoil using the Ffowcs Williams-Hawkings acoustic analogy
Characterisation of sheet cavity noise of a hydrofoil using the Ffowcs Williams-Hawkings acoustic analogy
Concerns about pollution of the marine environment with ship-induced noise and the scarcity of available numerical methods have recently stimulated significant amounts of research in hydroacoustic modelling. In this work, Large Eddy Simulation (LES) is used with Schnerr-Sauer mass-transfer cavitation model and a porous Ffowcs Williams-Hawkings (FW-H) acoustic analogy in order to simulate sheet cavitation on a NACA0009 hydrofoil. The aim is to investigate how well the proposed method captures the dominant noise sources associated with periodic sheet cavitation. The study further focuses on practical aspects, such as the importance of the non-linear FW-H term and convergence of the acoustic solution depending on the choice of the integration surface. This is done by correlating the radiated noise with integral and local flow quantities, such as cavity volume, lift coefficient and local vapour content. A key finding of the study is that the simulation framework is capable of correctly capturing the monopole nature of the sound generated by an oscillating cavity sheet. Results indicate that the numerical method is incapable of accurately resolving the flow during the final collapse stages of smaller cavity clouds, mainly due to mesh density limitations and the use of an incompressible flow assumption. Lack of small-scale bubble structures also causes the high-frequency range of the noise spectra to be under-predicted. Despite certain limitations the presented method offers a significant insight into the nature of cavitation-dominated noise and allows for some of the dominant sound generating mechanisms to be categorised.
hydroacoustics, cfd, cavitation, large eddy simulation, acoustic analogy, hydrofoil
0045-7930
8-23
Lidtke, Artur Konrad
5570c46b-09b5-4345-9f5c-7a5ed2a29ffc
Turnock, Stephen
d6442f5c-d9af-4fdb-8406-7c79a92b26ce
Humphrey, Victor
23c9bd0c-7870-428f-b0dd-5ff158d22590
Lidtke, Artur Konrad
5570c46b-09b5-4345-9f5c-7a5ed2a29ffc
Turnock, Stephen
d6442f5c-d9af-4fdb-8406-7c79a92b26ce
Humphrey, Victor
23c9bd0c-7870-428f-b0dd-5ff158d22590

Lidtke, Artur Konrad, Turnock, Stephen and Humphrey, Victor (2016) Characterisation of sheet cavity noise of a hydrofoil using the Ffowcs Williams-Hawkings acoustic analogy. Computers & Fluids, 130, 8-23. (doi:10.1016/j.compfluid.2016.02.014).

Record type: Article

Abstract

Concerns about pollution of the marine environment with ship-induced noise and the scarcity of available numerical methods have recently stimulated significant amounts of research in hydroacoustic modelling. In this work, Large Eddy Simulation (LES) is used with Schnerr-Sauer mass-transfer cavitation model and a porous Ffowcs Williams-Hawkings (FW-H) acoustic analogy in order to simulate sheet cavitation on a NACA0009 hydrofoil. The aim is to investigate how well the proposed method captures the dominant noise sources associated with periodic sheet cavitation. The study further focuses on practical aspects, such as the importance of the non-linear FW-H term and convergence of the acoustic solution depending on the choice of the integration surface. This is done by correlating the radiated noise with integral and local flow quantities, such as cavity volume, lift coefficient and local vapour content. A key finding of the study is that the simulation framework is capable of correctly capturing the monopole nature of the sound generated by an oscillating cavity sheet. Results indicate that the numerical method is incapable of accurately resolving the flow during the final collapse stages of smaller cavity clouds, mainly due to mesh density limitations and the use of an incompressible flow assumption. Lack of small-scale bubble structures also causes the high-frequency range of the noise spectra to be under-predicted. Despite certain limitations the presented method offers a significant insight into the nature of cavitation-dominated noise and allows for some of the dominant sound generating mechanisms to be categorised.

Text
2016 Lidtke - Characterisation of sheet cavity noise of a hydrofoil using the Ffowcs Williams-Hawkings acoustic analogy.pdf - Accepted Manuscript
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More information

Accepted/In Press date: 15 February 2016
e-pub ahead of print date: 26 February 2016
Published date: 18 May 2016
Keywords: hydroacoustics, cfd, cavitation, large eddy simulation, acoustic analogy, hydrofoil
Organisations: Fluid Structure Interactions Group, Faculty of Engineering and the Environment

Identifiers

Local EPrints ID: 389848
URI: http://eprints.soton.ac.uk/id/eprint/389848
ISSN: 0045-7930
PURE UUID: 14bbda81-d59d-4a79-99be-a1af623b4883
ORCID for Artur Konrad Lidtke: ORCID iD orcid.org/0000-0002-2687-3083
ORCID for Stephen Turnock: ORCID iD orcid.org/0000-0001-6288-0400
ORCID for Victor Humphrey: ORCID iD orcid.org/0000-0002-3580-5373

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Date deposited: 17 Mar 2016 10:01
Last modified: 18 Feb 2021 17:01

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