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Accuracy in Computational Aerodynamics Part 1: Stagnation Pressure
ISSN: 0148-7191, e-ISSN: 2688-3627
Published February 23, 1998 by SAE International in United States
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For the computation of the flow around a car there is typically an overprediction of stagnation and base pressure coefficient by 0.02 and 0.07 respectively causing an underprediction of total drag by about 0.01 - 0.02.
To determine the cause of the error in stagnation pressure several different effects have been investigated: length of inlet section, boundary conditions on the floor, mesh resolution, turbulence models and different flow solvers.
One major effect was found to be a short inlet section in the computational model, which caused an overprediction of the stagnation pressure.
The second major effect was insufficient resolution of the mesh along the stagnation line. More than 100 nodes along the stagnation line were necessary to avoid a significant pressure drop.
Finally the k-ε turbulence model caused overprediction of total pressure very close to the stagnation point. The use of an explicit algebraic Reynolds stress model removed this error. This turbulence model also improved prediction of pressure development along the front, in the spoiler region and at the front of the hood.
CitationAxelsson, N., Ramnefors, M., and Gustafsson, R., "Accuracy in Computational Aerodynamics Part 1: Stagnation Pressure," SAE Technical Paper 980037, 1998, https://doi.org/10.4271/980037.
- Ramnefors, M. Sköldheden, T. 1994 “Aerodynamic Computation as Part of the Design Process” Volvo Technology Report 2 1994 46 53 Volvo, Sweden
- Landby, P. Ramnefors, M. 1994 “CFD as a Tool in Styling Vehicles” Proceedings Second CFDS International Users Conference Pittsburg 7 9 December 1994 USA
- AEA Technology 1994 “Flow solver User Guide” UK
- Ramnefors, M. Perzon, S. Davidson, L. 1994 “Accuracy in Drag Prediction on Automobiles” Proceedings Conference on “Vehicle Aerodynamics” Royal Aeronautical Society Loughborough University of Technology 18 19 July 1994 England
- Dahlander, P. Jönson A. 1995 “On truncation errors in generalised curvilinear coordinate systems” Chalmer University of Technology Department of Thermo and Fluid Dynamics
- Perzon, S. Davidson, L. Ramnefors, M. 1995 “Computations on test case 2” 4'th ERCOFTAC Workshop on Refined Flow Modelling University of Kalsruhe 3 7 April 1995 Germany
- Daunius, O. 1995 “Computations on Test Case 4” 4'th ERCOFTAC Workshop on Refined Flow Modeling University of Kalsruhe 3 7 April 1995 Germany
- Perzon, S. Davidson, L. Ramnefors, M. 1995 “Reynolds Stress Modeling of Flow Separation on Curved Surfaces, a Status Report” Chalmers University of Technology Department of Thermo and Fluid Dynamics
- Ramnefors, M. Bensryd, R. Holmberg, E. Perzon, S. 1996 “Accuracy of Drag Predictions on Cars Using CFD - Effect of Grid Refinement and Turbulence Models” SAE Technical Paper 960681
- Perzon, S. Davidson, L. Ramnefors, M. 1996 “Computations on Test Case 4.5” 5'th ERCOFTAC Workshop on Refined Flow Modeling EDF, France
- Perzon, S. Davidson, L. Ramnefors, M. 1996 “Reynolds Stress Modeling of Separated Flows on Curved Surfaces” Advances in Turbulence VI Gavrilakis S. 77 78 Kluver Academic Publishers Netherlands
- Perzon, S. Davidson, L. Ramnefors, M. 1996 “Reynolds Stress Modeling of Complex Flows over Curved Surfaces” Flow Modeling and Turbulence Measurement VI Chen et al A. A. Balkema Rotterdam
- Kato, M. Launder B. E. 1993 “The Modeling of Turbulent Flow Around Stationary and Vibrating Square Cylinders” Proc. 9'th Symposium on Turbulent Shear Flows 10 4
- Wallin, S. Johansson, A. V. 1996 “A New Explicit Algebraic Reynolds Stress Turbulence Model Including an Improved Near Wall Treatment” Flow Modeling and Turbulence Measurement VI Chen et al A. A. Balkema Rotterdam
- Fletcher, C. 1991 “Computational Techniques for Fluid Dynamics” Springer-Verlag, Berlin
- Fluent Inc. 1996 “User's Guide for FLUENT/UNS & RAMPANT”
- Perzon, S. Sjögren, T. Jönson, A. 1997 “Accuracy in Computational Aerodynamics, Part2: Base Pressure”