This content is not included in your SAE MOBILUS subscription, or you are not logged in.
CFD Approach to Evaluate Wind-Tunnel and Model Setup Effects on Aerodynamic Drag and Lift for Detailed Vehicles
ISSN: 0148-7191, e-ISSN: 2688-3627
Published April 12, 2010 by SAE International in United States
Annotation ability available
Previous work by the authors showed the development of an aerodynamic CFD model using the Lattice Boltzmann Method for simulating vehicles inside the IVK Model-Scale Wind-Tunnel test-section. In both experiment and simulation, alternate configurations of the wind-tunnel geometry were studied to change the pressure distribution in the wind-tunnel test section, inducing a reduction in aerodynamic drag due to interference between the wind-tunnel geometry and the pressure on the surface of the vehicle. The wind-tunnel pressure distribution was modified by adding so-called “stagnation bodies” inside the collector to create blockage and to increase the pressure in the rear portion of the test section. The primary purpose of previous work was to provide a validated CFD approach for modeling wind-tunnel interference effects, so that these effects can be understood and accounted for when designing vehicles.
In this paper, the study using this CFD approach is extended to a broader range of effects of the wind-tunnel and model setup on the aerodynamic drag and lift. The effects of three different wind-tunnel pressure distributions are shown for detailed sedan and SUV models, presenting the interaction between vehicle shape and wind-tunnel interference effects. Additional effects were investigated, including the vehicle ride height and details in the geometry of the underbody.
Secondly, the possibility to apply standard wind-tunnel correction methods to the current data was examined for both vehicles. Corrections for wind-tunnel pressure gradient and open-jet wind-tunnel nozzle and collector blockage were applied to the data. In the simulation, the effect of wind-tunnel interference on the vehicle was examined by comparing to simulation with no wind-tunnel geometry and negligible blockage. Ideally, the corrected wind-tunnel data and the simulation with negligible blockage should match closely.
In summary, this paper provides a good foundation for using aerodynamic simulation to explore the various effects in a wind-tunnel, and provide a needed connection between wind-tunnel data and on-road performance.
CitationFischer, O., Kuthada, T., Mercker, E., Wiedemann, J. et al., "CFD Approach to Evaluate Wind-Tunnel and Model Setup Effects on Aerodynamic Drag and Lift for Detailed Vehicles," SAE Technical Paper 2010-01-0760, 2010, https://doi.org/10.4271/2010-01-0760.
Vehicle Aerodynamics, 2010
Number: SP-2269; Published: 2010-04-13
Number: SP-2269; Published: 2010-04-13
- Lietz, R. Mallick, S. Kandasamy, S. Chen, H. “Exterior Airflow Simulations Using a Lattice Boltzmann Approach,” SAE Technical Paper 2002-01-0596 2002
- Bartelheimer, W. Berechnung der Fahrzeugumströmung bei BMW: Validierung und Einsatz von Exa PowerFLOW, Tagung “Fahrzeug-Aerodynamik” Haus der Technik München 2001
- Parpais, S. Farce, J. Bailly, O. Genty, H. A Comparison of Experimental Investigations and Numerical Simulations around Two-box form Models, MIRA 4th Int. Conference of Vehicle Aerodynamics Warwick 2002
- Fischer, O. Kuthada, T. Wiedemann, J. Dethioux, P. Mann, R. Duncan, B. “CFD Validation Study for a Sedan Scale Model in an Open Jet Wind Tunnel,” SAE Technical Paper 2008-01-0325 2008
- Mallick, S. Remondi, S. Chen, H. Pervaiz, M. Developing CFD through Validation of Turbulence Models, MIRA 3th Int. Conference of Vehicle Aerodynamics Warwick 2000
- Wiedemann, J. Potthoff, J. “The New 5-Belt Road Simulation System of the IVK Wind Tunnels,” SAE Technical Paper 2003-01-0429 2003
- Schröck, D. Implementierung eines Programms zur Durchfuehrung und Auswertung von Stroemungsfeldmessungen im IVK-Modellwindkanal Institut für Verbrennungsmotoren und Kraftfahrwesen, Universität Stuttgart 2005
- Mercker, E. Wiedemann, J. “On the Correction of Interference Effects in Open Jet Wind Tunnels,” SAE Technical Paper 960671 1996
- Mercker, E. Wickern, G. Wiedemann, J. “Contemplation of Nozzle Blockage in Open Jet Wind-Tunnels in View of Different ‘Q’ Determination Techniques,” SAE Technical Paper 970136 1997
- Wickern, G. “On the Application of Classical Wind Tunnel Corrections for Automotive Bodies,” SAE Technical Paper 2001-01-0633 2001
- Wickern, G. “Gradient Effects on Drag due to Boundary-Layer Suction in Automotive Wind Tunnels,” SAE Technical Paper 2003-01-0655 2003
- Wiedemann, J. Fischer, O. Pang J. “Further Investigations on Gradient Effects,” SAE Technical Paper 2004-01-0670 2004
- Wickern, G. Schwartekopp, B. “Correction of Nozzle Gradient Effects in Open Jet Wind Tunnels,” SAE Technical Paper 2004-01-0669 2004
- Mercker, E. Cooper, K.R. Fischer, O. Wiedemann, J. “The influence of a Horizontal Pressure Distribution on Aerodynamic Drag in Open and Closed Wind Tunnels,” SAE Technical Paper 2005-01-0867 2005
- Mercker, E. Cooper, K.R. “A Two-Measurement Correction for the Effects of a Pressure Gradient on Automotive, Open-Jet, Wind Tunnel Measurements,” SAE Technical Paper 2006-01-0568 2006
- Wetzel, W. Übertragbarkeit aerodynamischer Beiwerte von Windkanalversuchen im Modellmaßstab auf reale Fahrzeuggeometrien (Validity of aerodynamic coefficients determined from wind tunnel tests in model scale for real full scale vehicle geometries) University of Karlsruhe 2001
- Perzon, S. “On Blockage Effects in Wind Tunnels - A CFD Study,” SAE Technical Paper 2001-01-0705 2001
- Yang, Z. Schenkel, M. Fadler, G.J. “Corrections of the Pressure Gradient Effects on Vehicle Aerodynamic Drag,” SAE Technical Paper 2003-01-0935 2003
- Yang, Z. Schenkel, M. “Assessment of Closed-Wall Wind Tunnel Blockage Using CFD,” SAE Technical Paper 2004-01-0672 2004
- Yang, Z. Nastov, A. Schenkel, M. “Further Assessment of Closed-Wall Wind Tunnel Blockage Using CFD,” SAE Technical Paper 2005-01-0868 2005
- Ewald, B. Wind Tunnel Wall Corrections 1998
- Künstner, R. Deutenbach, K.-R. Vagt, J.-D. “Measurement of Reference Dynamic Pressure in Open-Jet Automotive Wind Tunnels,” SAE Technical Paper 920344 1992
- Mercker, E. A Blockage Correction for Automotive Testing in a Wind Tunnel with Closed Test Section Journal of Wind Engineering and Industrial Aerodynamic 22 1986
- Fischer, O. Kuthada, T. Widdecke, N. Wiedemann, J. “CFD Investigations of Wind Tunnel Interference Effects,” SAE Technical Paper 2007-01-1045 2007
- Fischer, O. Kuthada, T. Wiedemann, J. CFD Validation Project on Vehicle Scale Models under the constraint of an open jet wind tunnel EUROMECH COLLOQUIUM 509 Vehicle Aerodynamics Berlin 2009