A complex ray-tracing tool for high-frequency mean-field flow interaction effects in jets
A complex ray-tracing tool for high-frequency mean-field flow interaction effects in jets
This paper presents a complex ray-tracing tool for the calculation of high-frequency Green’s functions in 3D mean field jet flows. For a generic problem, the ray solution suffers from three main deficiencies: multiplicity of solutions, singularities at caustics, and the determining of complex solutions. The purpose of this paper is to generalize, combine and apply existing stationary media methods to moving media scenarios. Multiplicities are dealt with using an equivalent two-point boundary-value problem, whilst non-uniformities at caustics are corrected using diffraction catastrophes. Complex rays are found using a combination of imaginary perturbations, an assumption of caustic stability, and analytic continuation of the receiver curve. To demonstrate this method, the ray tool is compared against a high-frequency modal solution of Lilley’s equation for an off-axis point source. This solution is representative of high-frequency source positions in real jets and is rich in caustic structures. A full utilization of the ray tool is shown to provide excellent results
1-17
American Institute of Aeronautics and Astronautics
Stone, J.T.
10d28c18-753c-4248-8f57-90cdc0bc774d
Self, R.H.
8b96166d-fc06-48e7-8c76-ebb3874b0ef7
Howls, C.J.
66d3f0f0-376c-4f7a-a206-093935e6c560
18 June 2014
Stone, J.T.
10d28c18-753c-4248-8f57-90cdc0bc774d
Self, R.H.
8b96166d-fc06-48e7-8c76-ebb3874b0ef7
Howls, C.J.
66d3f0f0-376c-4f7a-a206-093935e6c560
Stone, J.T., Self, R.H. and Howls, C.J.
(2014)
A complex ray-tracing tool for high-frequency mean-field flow interaction effects in jets.
In 20th AIAA/CEAS Aeroacoustics Conference.
American Institute of Aeronautics and Astronautics.
.
(doi:10.2514/6.2014-2757).
Record type:
Conference or Workshop Item
(Paper)
Abstract
This paper presents a complex ray-tracing tool for the calculation of high-frequency Green’s functions in 3D mean field jet flows. For a generic problem, the ray solution suffers from three main deficiencies: multiplicity of solutions, singularities at caustics, and the determining of complex solutions. The purpose of this paper is to generalize, combine and apply existing stationary media methods to moving media scenarios. Multiplicities are dealt with using an equivalent two-point boundary-value problem, whilst non-uniformities at caustics are corrected using diffraction catastrophes. Complex rays are found using a combination of imaginary perturbations, an assumption of caustic stability, and analytic continuation of the receiver curve. To demonstrate this method, the ray tool is compared against a high-frequency modal solution of Lilley’s equation for an off-axis point source. This solution is representative of high-frequency source positions in real jets and is rich in caustic structures. A full utilization of the ray tool is shown to provide excellent results
Text
advanced_example.pdf
- Accepted Manuscript
More information
e-pub ahead of print date: 13 June 2014
Published date: 18 June 2014
Organisations:
Applied Mathematics
Identifiers
Local EPrints ID: 371903
URI: http://eprints.soton.ac.uk/id/eprint/371903
PURE UUID: 8b399c46-ffc1-412c-b026-8f90e524698e
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Date deposited: 21 Nov 2014 11:56
Last modified: 16 Mar 2024 03:13
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Author:
J.T. Stone
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