Aero-acoustic oscillations inside large deep cavities

El Hassan, M., Labraga, L. and Keirsbulck, L. (2007). Aero-acoustic oscillations inside large deep cavities. In: Peter Jacobs, Tim McIntyre, Matthew Cleary, David Buttsworth, David Mee, Rose Clements, Richard Morgan and Charles Lemckert, 16th Australasian Fluid Mechanics Conference (AFMC). 16th Australasian Fluid Mechanics Conference (AFMC), Gold Coast, Queensland, Australia, (421-428). 3-7 December, 2007.

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Author El Hassan, M.
Labraga, L.
Keirsbulck, L.
Title of paper Aero-acoustic oscillations inside large deep cavities
Conference name 16th Australasian Fluid Mechanics Conference (AFMC)
Conference location Gold Coast, Queensland, Australia
Conference dates 3-7 December, 2007
Proceedings title 16th Australasian Fluid Mechanics Conference (AFMC)
Place of Publication Brisbane, Australia
Publisher School of Engineering, The University of Queensland
Publication Year 2007
Year available 2007
Sub-type Fully published paper
ISBN 978-1-864998-94-8
Editor Peter Jacobs
Tim McIntyre
Matthew Cleary
David Buttsworth
David Mee
Rose Clements
Richard Morgan
Charles Lemckert
Start page 421
End page 428
Total pages 8
Collection year 2007
Language eng
Abstract/Summary This investigation focuses on the pressure amplitude response, within two deep cavities characterized by their length over depth ratios (L/H = 0.2 and 0.41), under varying free stream velocity in a large wind tunnel. Experiments have shown that for deep rectangular cavities at low Mach number, oscillations of discrete frequencies can be produced. These oscillations appear when the free stream velocity becomes higher than a minimum value. In addition, as flow velocity is increased, upward jumps in oscillation frequency are observed in the two cavity configurations. Convection velocity of instabilities along the shear layer was measured using velocity cross-correlations. This study shows that the hydrodynamic modes of the cavity shear layer are correctly predicted by the Rossiter model when the convection velocity is determined and the empirical time delay is neglected. For L/H = 0.2 the first oscillation mode is observed on the spectrogram. For L/H = 0.41, both the first and the second mode have approximately the same amplitude. Time-resolved Particle image velocimetry measurements were performed to obtain the vorticity distribution during the oscillation cycle along the cavity shear layer. It is found that the number of structures in the cavity shear layer depends on the mode order of cavity oscillation.
Subjects 290501 Mechanical Engineering
Q-Index Code E1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Conference Paper
Collection: 16th Australasian Fluid Mechanics Conference
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Created: Wed, 19 Dec 2007, 10:34:32 EST by Laura McTaggart on behalf of School of Engineering