A study of air-to-water sound transmission, with application to semi-closed circuit diver breathing apparatus
A study of air-to-water sound transmission, with application to semi-closed circuit diver breathing apparatus
Noise reduction does not seem to have been of primary importance in the overall design of Semi-Closed Circuit Diver Breathing Apparatus (SCCBA). The noise radiation from the breathing apparatus is an important operational consideration as SCCBA sets are used for mine clearance purposes and they may acoustically trigger the mine whilst it is being defused. Trials were undertaken in order to establish the acoustic signature of SCCBA sets in the diver's working region. These established the SCCBA counterlung as the major contributor to the acoustic field immediately in front of the diver. The SCCBA counterlung was modelled as a thin rectangular enclosure of air, excited by an internal monopole sound source, radiating out into water. Three such models were developed: an initial monopole source air-to-water sound transmission model; a baffled front panel box model (ignoring diffraction and other box panel contrtibutions to the acoustic field in front of the diver); and, finally, a boundary element box model. The latter was used to model diffraction effects and the acoustic radiation from all six panels of the box.
There is a lack of published experimental data concerning the nature of the near field from a monopole sound source after transmission from air to water. This is because the near field is not of primary concern in most practical applications of air to water sound transmission. However, the near field is of primary importance for this research as it is within the diver's working region. The spatial FFT method (otherwise known as Near Field Acoustic Holography - NAH) was found to give the most accurate near field results for the initial box model. The significance of diffraction, side and rear panel contributions to the radiated acoustic field from the box was assessed using the two other box models and these contributions were found to be significant. Thus the sound radiation from the counterlung of the SCCBA set, in the diver's working region, should be predicted using a boundary element model.
University of Southampton
1994
Boyle, Susan Patricia
(1994)
A study of air-to-water sound transmission, with application to semi-closed circuit diver breathing apparatus.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
Noise reduction does not seem to have been of primary importance in the overall design of Semi-Closed Circuit Diver Breathing Apparatus (SCCBA). The noise radiation from the breathing apparatus is an important operational consideration as SCCBA sets are used for mine clearance purposes and they may acoustically trigger the mine whilst it is being defused. Trials were undertaken in order to establish the acoustic signature of SCCBA sets in the diver's working region. These established the SCCBA counterlung as the major contributor to the acoustic field immediately in front of the diver. The SCCBA counterlung was modelled as a thin rectangular enclosure of air, excited by an internal monopole sound source, radiating out into water. Three such models were developed: an initial monopole source air-to-water sound transmission model; a baffled front panel box model (ignoring diffraction and other box panel contrtibutions to the acoustic field in front of the diver); and, finally, a boundary element box model. The latter was used to model diffraction effects and the acoustic radiation from all six panels of the box.
There is a lack of published experimental data concerning the nature of the near field from a monopole sound source after transmission from air to water. This is because the near field is not of primary concern in most practical applications of air to water sound transmission. However, the near field is of primary importance for this research as it is within the diver's working region. The spatial FFT method (otherwise known as Near Field Acoustic Holography - NAH) was found to give the most accurate near field results for the initial box model. The significance of diffraction, side and rear panel contributions to the radiated acoustic field from the box was assessed using the two other box models and these contributions were found to be significant. Thus the sound radiation from the counterlung of the SCCBA set, in the diver's working region, should be predicted using a boundary element model.
This record has no associated files available for download.
More information
Published date: 1994
Identifiers
Local EPrints ID: 462803
URI: http://eprints.soton.ac.uk/id/eprint/462803
PURE UUID: 5bcf2635-4bb7-4e5e-ba88-174df952398b
Catalogue record
Date deposited: 04 Jul 2022 20:05
Last modified: 04 Jul 2022 20:05
Export record
Contributors
Author:
Susan Patricia Boyle
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