The present study focuses on the aerodynamics of pickup trucks. The flow about a generic pickup truck has been documented experimentally. The main objective is to gain a better understanding of the pickup truck aerodynamics through mean and unsteady pressure measurements as well as detailed flow field measurements using PIV (particle image velocimetry). Of particular interest and complexity are the symmetric and asymmetric separated vortex flows which develop behind the cab and the tailgate. A secondary objective is to obtain a comprehensive experimental data set for validation of CFD (computational fluid dynamics) models. The experiments were conducted at Reynolds numbers in the range of 5x105 - 8.5x105 in an open return wind tunnel equipped with two-frame digital PIV system. The mean pressure results of the pickup truck show that the pressure outside the tailgate is higher than inside the tailgate suggesting that the tailgate reduces aerodynamic drag. The rms (root-mean-square) values of pressure fluctuations at the cab back is very low and increases significantly towards the back of the bed and the tailgate top edge. Pressure fluctuation spectra indicate a spectral peak at a Strouhal number of approximately 0.07. Velocity field measurements of the near wake flow show a relatively quiet region behind the cab and no recirculating flow region in the symmetry plane behind the tailgate. Instead there is a strong downwash at the symmetry plane behind the tailgate. This downwash is due to the existence of a pair of counter-rotating vortices downstream of the tailgate. The downwash promotes attached flow behind the tailgate, thus resulting in a pressure recovery that reduces drag.
Experimental study of a pickup truck near wake
Journal of Wind Engineering and Industrial Aerodynamics ; 98 , 2 ; 100-112
2010
13 Seiten, 18 Quellen
Article (Journal)
English
Aerodynamik , numerische Strömungssimulation , Druckmessung , Reynolds-Zahl , Wirbelfluss , Windkanal , mechanischer Druck , Fahrzeugaerodynamik , Strömungsvisualisierung , Lastkraftwagen , Teilchenabbildgeschwindigkeitsmessung , Strömungsfeld , Fahrzeugraum , Kofferraumdeckel , Windkanalprüfung , Simulationsmodell , Turbulenzunterdrückung , Strouhal-Zahl , Geschwindigkeitsverteilung , Luftströmung
PIV Study of the Near Wake of a Pickup Truck
British Library Conference Proceedings | 2004
|