0
Research Papers: Flows in Complex Systems

Passive Control of Transonic Cavity Aeroacoustics

[+] Author and Article Information
David A. Roberts

Department of Power and Propulsion,  Cranfield University, Wharley End, Bedfordshire, MK43 0AL, UKd.roberts@cranfield.ac.uk

David G. MacManus

Department of Power and Propulsion,  Cranfield University, Wharley End, Bedfordshire, MK43 0AL, UKd.g.macmanus@cranfield.ac.uk

J. Fluids Eng 134(11), 111103 (Oct 24, 2012) (10 pages) doi:10.1115/1.4007593 History: Received November 15, 2011; Revised August 17, 2012; Published October 24, 2012

In recent years the continuing trend for the internalization of stores within an aircraft fuselage has led to a renewed interest in the field of cavity aeroacoustics. Open cavities exposed to transonic flow exhibit large pressure fluctuations which can result in damage to stores or components carried within the cavity. This study investigates the use of a passive resonant absorber based on Helmholtz resonators to attenuate the unsteady pressure fluctuations that arise in such cavity flows. The arrays are expected to remove energy from the high intensity cavity oscillations at the frequency to which they are tuned and therefore, to reduce the cavity noise. Six resonant arrays were designed to target individual Rossiter modes within a cavity. The arrays were tested in a small scale wind tunnel at both Mach 0.8 and Mach 0.9. The performance of the arrays were tested individually at both the front and rear wall of the cavity as well as in a combined arrangement. A peak attenuation of 14 dB was measured for an array at the front wall at Mach 0.9. A smaller attenuation of 8 dB was achieved when the same array was tested at Mach 0.8. Combined resonator installations at both the front and rear walls of the cavity further increased the peak sound pressure level (SPL) attenuation up to 18 dB at Mach 0.9. The investigation shows that passive resonant absorbers are a promising palliative method for the reduction of cavity acoustic modes at high subsonic speeds.

FIGURES IN THIS ARTICLE
<>
Copyright © 2012 by American Society of Mechanical Engineers
Topics: Cavities , Absorption
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 1

Schematic arrangement of perforated plate with common backing volume

Grahic Jump Location
Figure 2

Sketch of unsteady pressure instrumentation positions within cavity (not to scale)

Grahic Jump Location
Figure 3

Predicted absorption profiles for the six resonators in terms of absorption coefficient

Grahic Jump Location
Figure 4

Comparison between predicted and measured absorption profiles for a representative resonator case

Grahic Jump Location
Figure 5

SPL spectra for datum cavity (l/h = 5) measured at cavity ceiling x/l = 0.95 and tunnel background noise with no cavity for Mach 0.9

Grahic Jump Location
Figure 6

SPL spectra showing attenuation from ARRAY1 when installed at cavity front wall (FW) for Mach 0.9 flow. (Measured at cavity ceiling x/l = 0.95.)

Grahic Jump Location
Figure 7

SPL spectra showing attenuation from ARRAY1 when installed at cavity front wall (FW) for Mach 0.8 flow. (Measured at cavity ceiling x/l = 0.95.)

Grahic Jump Location
Figure 8

SPL spectra showing attenuation from ARRAY3 for Mach 0.9 rear wall installation (RW). (Measured at cavity ceiling x/l = 0.95.)

Grahic Jump Location
Figure 9

SPL spectra showing attenuation from ARRAY6. Rear wall installation (RW).

Grahic Jump Location
Figure 10

SPL spectra showing attenuation from ARRAY1 when installed at cavity rear wall (RW) for Mach 0.9. (Measured at cavity ceiling x/l = 0.95.)

Grahic Jump Location
Figure 11

SPL spectra showing attenuation from ARRAY2. Front wall installation (FW).

Grahic Jump Location
Figure 12

SPL spectra showing attenuation from ARRAY5. Front wall installation (FW).

Grahic Jump Location
Figure 13

SPL spectra showing attenuation for the case of combined installation with (a) ARRAY1 at the front wall (FW) and ARRAY2 at the rear wall (RW), (b) ARRAY2 at the front wall (FW) and ARRAY1 at the rear wall (RW) for Mach 0.9. (Measured at cavity ceiling x/l = 0.95.)

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In