Unsteady separated flows and acoustic feedback effects-prediction and observation

K. Hourigan, M. C. Welsh, M. C. Thompson, L. W. Welch, R. J. Downie, A. N. Stokes

Research output: Contribution to conferencePaperOtherpeer-review

Abstract

Results are presented of computational and experimental studies being conducted at the CSIRO to investigate the vortex structures shed from plates and aerofoils of various shapes under the control of either externally applied sound or flow-induced acoustic resonances. For strongly separated flows, numerical vortex methods are used to predict the large-scale vortex structures that are shed from bluff bodies and, together with the solution of the acoustic field, predict the modification due to the feedback of the acoustic field on the separating flow. Experimentally, smoke visualisation, hot wire anemometry, microphone and LDA measurements are carried out in wind tunnels to investigate the large-scale structuresshed from bluff bodies and the excitation of a transverse acousticresonant mode. Visualisation using hydrogen bubbles in a water tunnel with oscillating side walls shows vortex shedding from plates affected by a transverse perturbation simulating the acoustic mode excited in the wind tunnel. It is possible that low levels of acoustic feedback, which produce significant modification of flow, can remain undetected by the investigator, leading to erroneous comparisons between predictions and experiments.

Original languageEnglish
Publication statusPublished - 1 Jan 1988
Externally publishedYes
Event1st National Fluid Dynamics Conference, 1988 - Cincinnati, United States of America
Duration: 25 Jul 198828 Jul 1988

Conference

Conference1st National Fluid Dynamics Conference, 1988
CountryUnited States of America
CityCincinnati
Period25/07/8828/07/88

Cite this

Hourigan, K., Welsh, M. C., Thompson, M. C., Welch, L. W., Downie, R. J., & Stokes, A. N. (1988). Unsteady separated flows and acoustic feedback effects-prediction and observation. Paper presented at 1st National Fluid Dynamics Conference, 1988, Cincinnati, United States of America.
Hourigan, K. ; Welsh, M. C. ; Thompson, M. C. ; Welch, L. W. ; Downie, R. J. ; Stokes, A. N. / Unsteady separated flows and acoustic feedback effects-prediction and observation. Paper presented at 1st National Fluid Dynamics Conference, 1988, Cincinnati, United States of America.
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author = "K. Hourigan and Welsh, {M. C.} and Thompson, {M. C.} and Welch, {L. W.} and Downie, {R. J.} and Stokes, {A. N.}",
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note = "1st National Fluid Dynamics Conference, 1988 ; Conference date: 25-07-1988 Through 28-07-1988",

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Hourigan, K, Welsh, MC, Thompson, MC, Welch, LW, Downie, RJ & Stokes, AN 1988, 'Unsteady separated flows and acoustic feedback effects-prediction and observation' Paper presented at 1st National Fluid Dynamics Conference, 1988, Cincinnati, United States of America, 25/07/88 - 28/07/88, .

Unsteady separated flows and acoustic feedback effects-prediction and observation. / Hourigan, K.; Welsh, M. C.; Thompson, M. C.; Welch, L. W.; Downie, R. J.; Stokes, A. N.

1988. Paper presented at 1st National Fluid Dynamics Conference, 1988, Cincinnati, United States of America.

Research output: Contribution to conferencePaperOtherpeer-review

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T1 - Unsteady separated flows and acoustic feedback effects-prediction and observation

AU - Hourigan, K.

AU - Welsh, M. C.

AU - Thompson, M. C.

AU - Welch, L. W.

AU - Downie, R. J.

AU - Stokes, A. N.

PY - 1988/1/1

Y1 - 1988/1/1

N2 - Results are presented of computational and experimental studies being conducted at the CSIRO to investigate the vortex structures shed from plates and aerofoils of various shapes under the control of either externally applied sound or flow-induced acoustic resonances. For strongly separated flows, numerical vortex methods are used to predict the large-scale vortex structures that are shed from bluff bodies and, together with the solution of the acoustic field, predict the modification due to the feedback of the acoustic field on the separating flow. Experimentally, smoke visualisation, hot wire anemometry, microphone and LDA measurements are carried out in wind tunnels to investigate the large-scale structuresshed from bluff bodies and the excitation of a transverse acousticresonant mode. Visualisation using hydrogen bubbles in a water tunnel with oscillating side walls shows vortex shedding from plates affected by a transverse perturbation simulating the acoustic mode excited in the wind tunnel. It is possible that low levels of acoustic feedback, which produce significant modification of flow, can remain undetected by the investigator, leading to erroneous comparisons between predictions and experiments.

AB - Results are presented of computational and experimental studies being conducted at the CSIRO to investigate the vortex structures shed from plates and aerofoils of various shapes under the control of either externally applied sound or flow-induced acoustic resonances. For strongly separated flows, numerical vortex methods are used to predict the large-scale vortex structures that are shed from bluff bodies and, together with the solution of the acoustic field, predict the modification due to the feedback of the acoustic field on the separating flow. Experimentally, smoke visualisation, hot wire anemometry, microphone and LDA measurements are carried out in wind tunnels to investigate the large-scale structuresshed from bluff bodies and the excitation of a transverse acousticresonant mode. Visualisation using hydrogen bubbles in a water tunnel with oscillating side walls shows vortex shedding from plates affected by a transverse perturbation simulating the acoustic mode excited in the wind tunnel. It is possible that low levels of acoustic feedback, which produce significant modification of flow, can remain undetected by the investigator, leading to erroneous comparisons between predictions and experiments.

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Hourigan K, Welsh MC, Thompson MC, Welch LW, Downie RJ, Stokes AN. Unsteady separated flows and acoustic feedback effects-prediction and observation. 1988. Paper presented at 1st National Fluid Dynamics Conference, 1988, Cincinnati, United States of America.