The University of Southampton
University of Southampton Institutional Repository

The calculation of sound propagation in nonuniform flows: suppression of instability waves

The calculation of sound propagation in nonuniform flows: suppression of instability waves
The calculation of sound propagation in nonuniform flows: suppression of instability waves
Acoustic waves propagating through nonuniform flows are subject to convection and refraction. Most noise prediction schemes use a linear wave operator to capture these effects. However, the wave operator can also support instability waves that, for a jet, are the well-known Kelvin-Helmholtz instabilities. These are convective instabilities that can completely overwhelm the acoustic solution downstream of the source location. A general technique to filter out the instability waves is presented.
A mathematical analysis is presented that demonstrates that the instabilities are suppressed if a time-harmonic response is assumed, and the governing equations are solved by a direct solver in the frequency domain. Also, a buffer-zone treatment for a nonreflecting boundary condition implementation in the frequency domain is developed. The outgoing waves are damped in the buffer zone simply by adding imaginary values of appropriate sign to the required real frequency of the response. An analytical solution to a one-dimensional model problem, as well as numerical and analytical solutions to a two-dimensional jet instability problem, are provided. They demonstrate the effectiveness, robustness, and simplicity of the present technique.
0001-1452
80-88
Agarwal, Anurag
f63a9325-bd24-4341-8727-42a87cc5a163
Morris, Philip J.
8eb72640-9d4f-4772-8b1e-1665d897d835
Mani, Ramani
c678fc93-4da9-4013-9bee-d2e99c63e9f4
Agarwal, Anurag
f63a9325-bd24-4341-8727-42a87cc5a163
Morris, Philip J.
8eb72640-9d4f-4772-8b1e-1665d897d835
Mani, Ramani
c678fc93-4da9-4013-9bee-d2e99c63e9f4

Agarwal, Anurag, Morris, Philip J. and Mani, Ramani (2004) The calculation of sound propagation in nonuniform flows: suppression of instability waves. AIAA Journal, 42 (1), 80-88.

Record type: Article

Abstract

Acoustic waves propagating through nonuniform flows are subject to convection and refraction. Most noise prediction schemes use a linear wave operator to capture these effects. However, the wave operator can also support instability waves that, for a jet, are the well-known Kelvin-Helmholtz instabilities. These are convective instabilities that can completely overwhelm the acoustic solution downstream of the source location. A general technique to filter out the instability waves is presented.
A mathematical analysis is presented that demonstrates that the instabilities are suppressed if a time-harmonic response is assumed, and the governing equations are solved by a direct solver in the frequency domain. Also, a buffer-zone treatment for a nonreflecting boundary condition implementation in the frequency domain is developed. The outgoing waves are damped in the buffer zone simply by adding imaginary values of appropriate sign to the required real frequency of the response. An analytical solution to a one-dimensional model problem, as well as numerical and analytical solutions to a two-dimensional jet instability problem, are provided. They demonstrate the effectiveness, robustness, and simplicity of the present technique.

Text
AIAA-619-379.pdf - Version of Record
Restricted to Repository staff only

More information

Published date: 2004

Identifiers

Local EPrints ID: 37988
URI: http://eprints.soton.ac.uk/id/eprint/37988
ISSN: 0001-1452
PURE UUID: 2b5166b1-cffa-4794-85c3-c53f599d92f2

Catalogue record

Date deposited: 26 May 2006
Last modified: 16 Dec 2019 19:21

Export record

Contributors

Author: Anurag Agarwal
Author: Philip J. Morris
Author: Ramani Mani

University divisions

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×