This content is not included in your SAE MOBILUS subscription, or you are not logged in.
Experimental Investigations and Computations of Unsteady Flow Past a Real Car Using a Robust Elliptic Relaxation Closure with a Universal Wall Treatment
ISSN: 0148-7191, e-ISSN: 2688-3627
Published April 16, 2007 by SAE International in United States
Annotation ability available
In the present work we investigated experimentally and computationally the unsteady flow around a BMW car model including wheels*. This simulation yields mean flow and turbulence fields, enabling the study aerodynamic coefficients (drag and lift coefficients, three-dimensional/spatial wall-pressure distribution) as well as some unsteady flow phenomena in the car wake (analysis of the vortex shedding frequency). Comparisons with experimental findings are presented. The computational approach used is based on solving the complete transient Reynolds-Averaged Navier-Stokes (TRANS) equations. Special attention is devoted to turbulence modelling and the near-wall treatment of turbulence. The flow calculations were performed using a robust, eddy-viscosity-based ζ - ƒ turbulence model in the framework of the elliptic relaxation concept and in conjunction with the universal wall treatment, combining integration up to the wall and wall functions.
CitationBasara, B., Aldudak, F., Jakirlić, S., Tropea, C. et al., "Experimental Investigations and Computations of Unsteady Flow Past a Real Car Using a Robust Elliptic Relaxation Closure with a Universal Wall Treatment," SAE Technical Paper 2007-01-0104, 2007, https://doi.org/10.4271/2007-01-0104.
SAE 2007 Transactions Journal of Passenger Cars: Mechanical Systems
Number: V116-6; Published: 2008-08-15
Number: V116-6; Published: 2008-08-15
- Abdel Azim A.F., 1994, “An Experimental Study of the Aerodynamic Interference between Road Vehicles”, SAE 940422.
- AVL AST, 2004, AVL Swift/Fire Manual 8.4, AVL List GmbH, Graz.
- Basara, B., and Tibaut, P., 2002, “Time dependent vs. steady state calculations of external aerodynamics”, Proc. of the Aerodynamics of Heavy Vehicles: Trucks, Buses and Trains, Lecture Notes in Applied and Computational Mechanics, Vol. 19, pp. 107-119, Springer.
- Basara, B., 2006a, “An Eddy Viscosity Transport Model Based on Elliptic Relaxation Approach”, AIAA J., Vol. 44, pp. 1686-1690.
- Basara, B., Przulj, V., and Tibaut, P., 2002, “On the calculation of external aerodynamics: Industrial Benchmarks,” SAE 2001-01-0701.
- Baxendele, A.J., Graysmith, J.L., Howell, J.P. and Hayness, T., 1996, “The CFD Investigation of Flow Separation over a Simple Vehicle Model,” Proc, RaeS Vehicle Aerodynamics Conference, Loughborough University, U.K.
- Bredberg, J., and Davidson, L., 2004, “Low-Reynolds Number Turbulence Models: An Approach for Reducing Mesh Sensitivity,” J. of Fluids Engineering, Vol. 126, pp. 14-21.
- Demirdzic, I., Muzaferija, S., 1995, “Numerical Method for Coupled Fluid Flow, Heat Transfer and Stress Analysis Using Unstructured Moving Meshes with Cells of Arbitrary Topology.” Comp. Methods Appl. Mech. Eng., Vol. 125, pp. 235-255.
- Durbin, P.A., 1991, “Near-wall turbulence closure modeling without damping functions,” Theoretical CFD, Vol. 3, pp. 1-13
- Esch, T., Menter, R.F., 2003, “Heat Transfer Predictions Based on Two-Equation Turbulence Models With Advanced Wall Treatment,” Turbulence, Heat and Mass Transfer, 4, 633-640.
- Ferziger, J., Peric, M., 1997, Computational Methods for Fluid Dynamics, Springer, Berlin.
- Gilliéron P., Noger C., 2003, “Banc Expérimental d'analyse Phénomènes Aérodynamiques Générés par le Dépassement de deux Véhicules Automobiles”, 16éme Congrès Français de Mécanique.
- Girimaji S.S., Abdol-Hamid, K.S., 2005, “Partially-averaged Navier Stokes Model for Turbulence: Implementation and Validation,” AIAA Paper 2005-0502, 43rd AIAA Aerospace Sciences Meeting and Exhibition, Reno, Nevada
- Hanjalic, K., Popovac, M., Hadziabdic, M., 2004, “A robust near-wall elliptic-relaxation eddy-viscosity turbulence model for”, Int. J. of Heat and Fluid Flow, 25, 1047-1051.
- Hucho W., Krüger L., Lentzen M., 2005, “Aerodynamik des Automobiles”, Vieweg.
- Hupertz, B., Blumcke, E. and Wustenberg, H., 1996, “Employment of numerical simulation in the field of external vehicle aerodynamics: A status report,” VDI Berichte, 1238, p. 369.
- Jakirlić, S., Kniesner, B., Šarić S., Hanjalić, K., 2006 “Merging near-wall RANS models with LES for separating and reattaching flows,” ASME Joint U.S.-European Fluids Engineering Summer Meeting: Symposium on “DNS, LES and Hybrid RANS/LES Techniques”, Miami, FL, USA, July, 17-20, Paper No. FEDSM2006-98039
- Kader, B.A., 1981, “Temperature and Concentration Profiles in Fully Turbulent Boundary Layers,” Int. J. Heat and Mass Transfer, Vol. 24, pp. 1541-1544.
- Khalighi, B., Zhang, S., Koromilas, C., Balkanyi, S.R., Bernal, P., Iaccarino, G., Moin, P., 2001, “Experimental and computational study of unsteady wake flow behind a bluff body with a drag reduction device,” SAE 2001-01-1042.
- Makowsky, F.T. and Kim, S.E., 2000, “Advances in External-Aero Simulation of Ground Vehicles Using the Steady RANS Equations,” SAE 2000-01-0484, Detroit, Michigan, 6-9 March.
- Marthur, S.R., Murthy, J,Y., 1997, “A Pressure Based Method for Unstructured Meshes”, Numerical Heat Transfer B, Vol. 31, pp. 195-215.
- Meijerink, J.A., Van Der Vorst, H.A., 1981, “Guidelines for the Usage of Incomplete Decompositions in Solving Sets of Linear Equations as They Occur in Practical Problems,” J. Computational Physics, Vol. 44, pp. 134-155.
- Muzaferija, S., 1994, Adaptive Finite Volume Method for Flow Predictions Using Unstructured Meshes and Multigrid Approach, PhD Thesis, University of London.
- Popovac, M., Hanjalic, K., 2005, “Compound Wall Treatment for RANS Computation of Complex Turbulent Flows”, Third MIT Conf. On Comp. Fluid and Solid Mech., edited by Bathe K., Vol. 1, Elsevier, 802-806.
- Przulj, V., Basara, B., 2001, “Bounded Convection Schemes for Unstructured Grids”, AIAA Paper 2001-2593.
- Speziale, C.G., Sarkar, S., Gatski, T.B., 1991, “Modeling the Pressure-Strain Correlation of Turbulence: An Invariant Dynamical Systems Approach,” J. Fluid Mech., Vol. 227, pp. 245-272.
- Sweby, P.K., 1984, “High Resolution Schemes Using Flux Limiters for Hyperbolic Conservation Laws,” SIAM Journal Numer. Anal., Vol. 21, pp. 995-1011.
- Széchényi, E., 2004, “The Overtaking Process of Vehicles”, Progress in Vehicle Aerodynamics III-Unsteady Flow Effects.
- Tsuei L., Savas Ö., 2000, “A Wind Tunnel Investigation of the Transient Aerodynamic Effects on a Four Car Platoon during Passing Manoeuvres”, SAE 2000-01-0875.
- Yamamoto, S. et al, 1996, “Aerodynamic Influence of a Passenger Vehicle on the Stability of the Other Vehicles”, JSAE9730074.