This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Wind Tunnel Pulsations and their Active Suppression
Technical Paper
2000-01-0869
ISSN: 0148-7191, e-ISSN: 2688-3627
Annotation ability available
Sector:
Event:
SAE 2000 World Congress
Language:
English
Abstract
Low-frequency pressure fluctuations which occur at certain flow speeds are an undesired feature in many open jet wind tunnels. This so called ‘wind tunnel pumping’ affects the aerodynamic quality of the flow and thus the quality of the measured data. In this paper a novel approach is presented to control the pulsation phenomenon by active damping of the acoustic resonant modes of the wind tunnel circuit. The acoustic mechanism of the resonance effect was investigated using a 1/20 scale pilot wind tunnel with a complete and detailed representation of test section, ducting, turning vanes and fan. The newly devised Active Resonance Control (ARC) System essentially consists of a microphone which picks up the pressure fluctuations in the plenum, a loudspeaker which is mounted in the tunnel wall and a time delay to adjust the phase relation between the microphone signal and the loudspeaker output. The ARC system reduces the periodic pressure fluctuations by 20 dB and completely eliminates the periodic velocity fluctuations. Based on the experiences with the pilot wind tunnel an ARC System was implemented in the new Audi aeroacoustic wind tunnel. The ARC System eliminates the low-frequency flow fluctuations without introducing additional noise into the wind tunnel and thus allows high-quality aerodynamic and acoustic measurements over the entire velocity range.
Recommended Content
Authors
Topic
Citation
Wickern, G., von Heesen, W., and Wallmann, S., "Wind Tunnel Pulsations and their Active Suppression," SAE Technical Paper 2000-01-0869, 2000, https://doi.org/10.4271/2000-01-0869.Also In
SAE 2000 Transactions Journal of Passenger Cars - Mechanical Systems
Number: V109-6; Published: 2001-09-15
Number: V109-6; Published: 2001-09-15
References
- Holthusen, H. Kooi, J.W. Model and Full Scale Investigations of the Low Frequency Vibration Phenomena of the DNW Open Jet 1997
- Ackermann, U. Strömungsakustische Modelluntersuchungen für einen Freistrahl-Windkanal (Flow-Acoustic Model Experiments for an Open Jet Wind Tunnel) Zeitschrift für Lärmbekämpfung 38 1991 10 18 1991
- Seiferth, R. Pre-Calculation and Removal of Oscillations in Free-jet Wind Tunnels AVA Monographs on German Aeronautical Research carried out since 1939 D4.4 Ministery of Aircraft Production Volkenrode Rept. and Trans. 947 August 1947
- Arnette, S.A. Buchanan, T.D. Zabat, M. An Investigation of pressure Pulsations in Open Jet Automotive Wind Tunnels 2 nd MIRA International Conference on Vehicle Aerodynamics 20-21 Oct. 1998 Coventry, UK 1998
- Wiedemann, J. Wickern, G. Ewald, B. Mattern, C. Audi Aero-acoustic Wind Tunnel SAE Paper 930300 1993
- Michel, U. Froebel, E. Turbulence at far downstream Positions in the Open Working Section of the German-Dutch Wind Tunnel DNW 1985
- Wehrmann, O. Akustische Steuerung der turbulenten Anfachung (Acoustic Control of Turbulent Excitation) 1957
- Ackermann, U. Instabilitätswellen in einem runden, turbulenten Freistrahl und ihre Schallabstrahlung (Instability Waves in a Round Turbulent Free Jet and their Sound Radiation) University of Göttingen 1976
- Ahuja, K.K. Massey, K.C. D'Agostino, M.S. Flow/Acoustic Interaction in Open Jet Wind Tunnels 1997
- Rossiter, J. E. Wind-Tunnel Experiments on the Flow over Rectangular Cavities at Subsonic and Transsonic Speeds Ministry of Aviation London 1964
- Welch, M.C. Stokes, A.N. Parker, R. Flow-resonant Sound Interaction in a Duct containing a Plate, Part I: Semi-Circular Leading Edge Journal of Sound and Vibration 95 3 305 323 1984
- Wallmann, S. Strömungstechnische und strömungsakustische Untersuchungen an einem Windkanal (Aerodynamic and Aeroacoustic Testing of a Wind Tunnel) 1996
- Wallmann, S. Untersuchungen am Modell des Aeroakustik Windkanals der Audi AG (Pilot tunnel experiments for the Audi Wind Tunnel) 1997
- von Heesen, W. 1998 1999
- Katzmeier Über das Verhalten von Flügelflächen bei periodischer Änderung der Geschwindigkeit und der Richtung (On the Behavior of Wings under Periodic Changes of Velocity and Angle of Attack) 1922
- Wickern, G. Wallmann, S. von Heesen, W. Wind Tunnel
- Lindener, N. Wickern, G. The Audi Aeroacoustic Wind Tunnel: Final Design and First Operational Experience SAE 2000-01-0868 2000