This content is not included in your SAE MOBILUS subscription, or you are not logged in.
Computational Study of Drag Reduction of Models of Truck-Shaped Bodies in Ground Effect by Active Flow Control
ISSN: 0148-7191, e-ISSN: 2688-3627
Published April 08, 2013 by SAE International in United States
Annotation ability available
In U.S., the ground vehicles consume about 77% of all (domestic and imported) petroleum; 34% is consumed by automobiles, 25% by light trucks and 18% by large heavy-duty trucks and trailers. It has been estimated that 1% increase in fuel economy can save 245 million gallons of fuel/year. Furthermore, the fuel consumption by ground vehicles accounts for over 70% of CO₂ and other greenhouse gas (GHG) emissions in U.S. Most of the usable energy from the engine (after accounting for engine losses) at highway speed of 55 mph goes into overcoming the aerodynamic drag (53%) and rolling resistance (32%); only 9% is required for auxiliary equipment and 6% is used by the drivetrain. 15% reduction in aerodynamic drag at highway speed of 55 mph can result in about 5-7% in fuel saving. The goal of this paper is to demonstrate by numerical simulations on generic truck models that the active flow control (AFC) technology can be easily deployed/retrofitted to reduce the aerodynamic drag by 15-20% at highway speed. It is important to note however that these estimates of drag reduction are based on CFD studies performed on simple generic truck models; for actual trucks the values will be much lower because of considerable complexity of the configurations.
For AFC, we employ a few oscillatory jet actuators (also known as synthetic jet actuators) at the rear face of the ground vehicle. These devices are easy to incorporate into the existing vehicles at very modest cost. The cost may come down significantly for a large volume of actuators, especially for ground vehicles. Numerical simulations are performed using the Unsteady Reynolds-Averaged Navier-Stokes (URANS) equations on solution adaptive structured grids in conjunction with a two-equation realizable k-ε turbulence model. The commercially available grid generator "GAMBIT" and the CFD solver "FLUENT" are employed in the simulations. Three generic ground vehicle configurations are considered in the simulations; the experimental data has been available for these configurations without and with AFC. The numerical simulations are in good agreement with the experimental data. In addition, a computational study is performed for one of the generic truck models to include the ground to evaluate its effect on aerodynamic drag without and with AFC. These studies clearly demonstrate that the AFC technique using synthetic jet actuators can be effectively employed to achieve significant reduction (10-15%) in aerodynamic drag with a potential of reducing the fuel consumption by 5-7%.
CitationAgarwal, R., "Computational Study of Drag Reduction of Models of Truck-Shaped Bodies in Ground Effect by Active Flow Control," SAE Technical Paper 2013-01-0954, 2013, https://doi.org/10.4271/2013-01-0954.
- Salari, K., “DOE's Effort to Reduce Truck Aerodynamic Drag through Joint Experiments and Computations,” LLNL-PRES-401649, 28 February 2008.
- Barber, T., “Aerodynamic Ground Effect: A Case Study of the Integration of CFD and Experiments,” International Journal of Vehicle Design, pp. 299-315, 2006.
- Bayraktar, I., Landman, D., and Bayraktar, T., “Experimental Measurement and Computational Solutions for Aerodynamic Forces on an Ahmed Body at Various Ground Clearances,” Proc. of ASME International Mechanical Engineering Congress, Washington DC, pp.223-233, 2003.
- Baysal, O. and Bayraktar, I., “Computational Simulations for the External Aerodynamics of Heavy Trucks,” SAE Technical Paper 2000-01-3501, 2000, doi: 10.4271/2000-01-3501.
- Nishino, T. and Roberts, G., “Absolute and Convective Instabilities of Two-Dimensional Bluff Body Wakes in Ground Effect,” European Journal of Mechanics B/Fluids, pp. 539-551, 2008.
- Bellman, M., Straccia, J., Morgan, B., Maschmeyer, K., and Agarwal, R. K., “Improving Genetic Algorithm Efficiency with an Artificial Neural Network for Optimization of Low Reynolds Number Airfoils,” AIAA Paper 2009-1096, AIAA Aerospace Sciences Meeting, Orlando, FL, 5-8 January 2009.
- Bellman, M., Naber, J., and Agarwal, R. K., “Numerical Drag Reduction Studies of Generic Truck Models Using Active Flow Control,” AIAA Paper 2009-4013, AIAA Fluid Dynamics Conference, San Antonio, TX, 22-25 June 2009.
- Pinzon, C. F. and Agarwal, R. K. “An experimental and Computational study of a Zero-Net-Mass-Flux (ZNMF) Actuator,” AIAA Paper 2008-0559, 46th AIAA Aerospace Sciences Meeting, Reno, NV, 7-10 January 2008.
- Seifert, A., Stalnov, O., Sperber, D., Arwatz, G., Palei, V., David, S., Dayan, I., and Fono, I., “Large Trucks Drag Reduction Using Active Flow Control,” AIAA Paper, AIAA Aerospace Sciences Meeting, Reno, NV, January 2008.
- Pastoor, M., Henning, L., Noack, B. R., King, R., and Tadmor, G., “Feedback Shear Layer Control for Bluff Body Drag Reduction,” Journal of Fluid Mechanics, Vol. 608, pp.161-196, 2008.
- Wassen, E and Thiele, F., “Drag Reduction for a Generic Car Model Using Steady Blowing,” AIAA Paper 2008-3771, AIAA Fluid Dynamics Conference, Seattle, June 2008.
- FLUENT 6.3: Flow Modeling Software, Ansys Inc., 2007.
- GAMBIT 6.2: Geometry and Mesh Generation Preprocessor, Ansys Inc., 2007.
- Bellman M., “Numerical Drag Reduction Studies of Generic Truck Models Using Passive and Active Flow Control,” M.S. Thesis, Washington University in St. Louis, June 2009
- Siewny, M. “Numerical Drag Reduction Studies of Generic Truck Models in Ground Effect Using Active Flow Control,” REU Report, Washington University in St. Louis, August 2009.