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Contemplation of Nozzle Blockage in Open Jet Wind-Tunnels in View of Different ‘Q’ Determination Techniques
ISSN: 0148-7191, e-ISSN: 2688-3627
Published February 24, 1997 by SAE International in United States
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This paper deals with the correction of aerodynamic interference effects taking place between the nozzle of an open jet wind tunnel and a test model. In order to deduce correct aerodynamic coefficients these interference effects have to be allowed for in the determination of the correct wind tunnel speed. In open jet wind tunnels basically two different methods are used to determine the tunnel speed. One is the so-called nozzle-method, utilizing the pressure difference down the nozzle to determine the nozzle exit velocity or tunnel speed. The other procedure is the so-called plenum-method, where the pressure difference between the settling chamber and the surrounding plenum chamber of the test section is measured and used. In this paper it is shown that both methods yield a systematic error, since the velocity distribution in the nozzle differs from the velocity distribution in an unbounded stream measured at the same distance from the model. In order to compensate for this effect a correction factor is derived with the aid of a simple potential flow model.
CitationMercker, E., Wickern, G., and Weidemann, J., "Contemplation of Nozzle Blockage in Open Jet Wind-Tunnels in View of Different ‘Q’ Determination Techniques," SAE Technical Paper 970136, 1997, https://doi.org/10.4271/970136.
- Mercker E. Wiedemann J. On the Correction of Interference Effects in Open Jet Wind Tunnels SAE Technical Paper 960671 1996
- Kuhn A. 1995
- Künstner R. Deutenbach K.R. Vagt J.D. Measurement of Reference Dynamic Pressure in Open Jet Automotive Wind Tunnels SAE Technical Paper 920344 1992
- Deutenbach K.R. Influence of Plenum Dimensions on Drag Measurements in 3/4-Open-Jet Automotive Wind Tunnels SAE Technical Paper 95100 1995
- Aerodynamic Testing of Road Vehicles SAE Surface Vehicle Information Report J2071 1990