The University of Southampton
University of Southampton Institutional Repository

A measurement based study of the acoustics of pipe systems with flow

English, Emmet J. (2010) A measurement based study of the acoustics of pipe systems with flow University of Southampton, Institute of Sound and Vibration Research, Doctoral Thesis , 175pp.

Record type: Thesis (Doctoral)

Abstract

The focus of this thesis is the measurement of specific aeroacoustic properties in ducts at frequencies below the cut-on frequency of the first higher order mode. A body of measurement results are presented which highlight the effect of flow on some of the aeroacoustic characteristics in ducts as well as describe the aeroacoustic sources of an in-duct orifice and a simple expansion chamber. The results have been compared with published theory where appropriate. Important developments from measurements of the acoustic characteristics of a simple duct with flow include a new experimental method to determine the viscothermal attenuation coefficient. In addition, pressure reflection coefficient measurements of an unflanged duct with flow with two different edge conditions are used in conjunction with a numerical model developed by Gabard [1] to determine the extent of vorticity shed from the duct termination. A novel method is presented for the measurement of aeroacoustic source strengths in ducts with flow. The source is defined in terms of acoustic power and is determined by measuring the acoustic power flux both upstream and downstream of the source region in a duct. The method adopts a plane wave approximation and was assessed experimentally by creating a source in a duct at a number of known frequencies and modifying its magnitude by a known amount. The source measurement technique is applied to an in-duct orifice. The results are used to determine the spectral characteristic and velocity dependence of the source. The results indicate that the duct-to-orifice area ratio has a important effect on the spectral characteristics and velocity dependence of the source. New measurements of the aeroacoustic source strength of a simple flow excited expansion chamber are presented. The results indicate that lock-on flow tones occur when hydrodynamic modes which form in the chamber match the tailpipe resonant frequencies. The results are compared with predictions of a model based on describing function theory

PDF P2673.pdf - Other
Download (5MB)

More information

Published date: July 2010
Organisations: University of Southampton, Fluid Structure Interactions Group

Identifiers

Local EPrints ID: 198723
URI: http://eprints.soton.ac.uk/id/eprint/198723
PURE UUID: b24d887f-3cf0-4f19-bd17-f751c8d83fc2
ORCID for Keith Holland: ORCID iD orcid.org/0000-0001-7439-2375

Catalogue record

Date deposited: 06 Oct 2011 13:50
Last modified: 18 Jul 2017 11:17

Export record

Contributors

Author: Emmet J. English
Thesis advisor: P.O.A.L. Davies
Thesis advisor: Keith Holland ORCID iD

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.

×