Acoustic Scattering for Rotational and Translational Symmetric Structures in Nonuniform Potential Flow

Karimi, M; Croaker, P; Peake, N; Kessissoglou, N

Acoustic Scattering for Rotational and Translational Symmetric Structures in Nonuniform Potential Flow

Karimi, M

Croaker, P Peake, N Kessissoglou, N

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Publisher:: American Institute of Aeronautics and Astronautics
Publication Type:: Journal Article
Citation:: AIAA Journal: devoted to aerospace research and development, 2017, 55, (10), pp. 3318-3327
Issue Date:: 2017-05-31

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Field	Value	Language
dc.contributor.author	Karimi, M https://orcid.org/0000-0002-2949-5364
dc.contributor.author	Croaker, P
dc.contributor.author	Peake, N
dc.contributor.author	Kessissoglou, N
dc.date.accessioned	2022-08-29T00:56:32Z
dc.date.available	2022-08-29T00:56:32Z
dc.date.issued	2017-05-31
dc.identifier.citation	AIAA Journal: devoted to aerospace research and development, 2017, 55, (10), pp. 3318-3327
dc.identifier.issn	0001-1452
dc.identifier.issn	1533-385X
dc.identifier.uri	http://hdl.handle.net/10453/160999
dc.description.abstract	An efficient approach is proposed to predict acoustic scattering with nonuniform potential flow effects for structures with rotational and translational symmetries. The convected wave equation is transformed to Helmholtz and Laplace equations using a time transformation. The boundary-element method is used to formulate scattering by rotationally symmetric structures as two separate block circulant matrix equations and, similarly, as two separate block Toeplitz matrix equations for structures with translational symmetry. Discrete Fourier transform is employed to solve the block circulant systems. The block Toeplitz systems are solved using the generalized minimal residual method along with the discrete Fourier transform. Solving the convected wave equation using structured matrices significantly reduces computational time and storage requirements. To demonstrate the application of the formulation, two exterior acoustic case studies are considered. The first case study examines acoustic scattering from a sphere submerged in potential flow under monopole source excitation. Directivity plots obtained using the proposed technique are compared with analytical results. The second case study examines flow-induced noise generated by a rigid cylinder immersed in low-Mach-number flow, with the effect of mean flow on the scattered acoustic field taken into account using nonuniform potential flow. The fluctuating flowfield is obtained using an incompressible computational fluid dynamics solver. Acoustic sources based on Lighthill's analogy are extracted from the flowfield data using a high-order reconstruction scheme. Results from the hybrid computational fluid dynamics-boundaryelement method technique are presented for turbulent flow past the cylinder, with Reynolds number based on cylinder diameter of ReD = 46;000 and Mach numberM = 0.21. The aeroacoustic results are compared with data from literature.
dc.language	English
dc.publisher	American Institute of Aeronautics and Astronautics
dc.relation.ispartof	AIAA Journal: devoted to aerospace research and development
dc.relation.isbasedon	10.2514/1.J055844
dc.rights	info:eu-repo/semantics/closedAccess
dc.subject	0901 Aerospace Engineering, 0905 Civil Engineering, 0913 Mechanical Engineering
dc.subject.classification	Aerospace & Aeronautics
dc.title	Acoustic Scattering for Rotational and Translational Symmetric Structures in Nonuniform Potential Flow
dc.type	Journal Article
utslib.citation.volume	55
utslib.for	0901 Aerospace Engineering
utslib.for	0905 Civil Engineering
utslib.for	0913 Mechanical Engineering
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Engineering and Information Technology
pubs.organisational-group	/University of Technology Sydney/Faculty of Engineering and Information Technology/School of Mechanical and Mechatronic Engineering
utslib.copyright.status	closed_access	*
pubs.consider-herdc	false
dc.date.updated	2022-08-29T00:56:31Z
pubs.issue	10
pubs.publication-status	Published
pubs.volume	55
utslib.citation.issue	10

Abstract:

An efficient approach is proposed to predict acoustic scattering with nonuniform potential flow effects for structures with rotational and translational symmetries. The convected wave equation is transformed to Helmholtz and Laplace equations using a time transformation. The boundary-element method is used to formulate scattering by rotationally symmetric structures as two separate block circulant matrix equations and, similarly, as two separate block Toeplitz matrix equations for structures with translational symmetry. Discrete Fourier transform is employed to solve the block circulant systems. The block Toeplitz systems are solved using the generalized minimal residual method along with the discrete Fourier transform. Solving the convected wave equation using structured matrices significantly reduces computational time and storage requirements. To demonstrate the application of the formulation, two exterior acoustic case studies are considered. The first case study examines acoustic scattering from a sphere submerged in potential flow under monopole source excitation. Directivity plots obtained using the proposed technique are compared with analytical results. The second case study examines flow-induced noise generated by a rigid cylinder immersed in low-Mach-number flow, with the effect of mean flow on the scattered acoustic field taken into account using nonuniform potential flow. The fluctuating flowfield is obtained using an incompressible computational fluid dynamics solver. Acoustic sources based on Lighthill's analogy are extracted from the flowfield data using a high-order reconstruction scheme. Results from the hybrid computational fluid dynamics-boundaryelement method technique are presented for turbulent flow past the cylinder, with Reynolds number based on cylinder diameter of ReD = 46;000 and Mach numberM = 0.21. The aeroacoustic results are compared with data from literature.

Please use this identifier to cite or link to this item:

http://hdl.handle.net/10453/160999