Aerodynamic study of three cars in tandem using computational fluid dynamics

Authors

  • H. Abdul-Rahman Department of Mechanical and Manufacturing Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia. Phone: +60389216522; Fax: +60389118314
  • H. Moria Department of Mechanical Engineering Technology, Yanbu Industrial College, Yanbu Al-Sinaiyah City 41912, Saudi Arabia
  • M.R. Rasani Department of Mechanical and Manufacturing Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia. Phone: +60389216522; Fax: +60389118314

DOI:

https://doi.org/10.15282/15.3.2021.02.0646

Keywords:

Computational fluid dynamics (CFD), platoon, aerodynamic force, drag coefficient

Abstract

Aerodynamics of vehicles account for nearly 80% of fuel losses on the road. Today, the use of the Intelligent Transport System (ITS) allows vehicles to be guided at a distance close to each other and has been shown to help reduce the drag coefficients of the vehicles involved. In this article, the aim is to investigate the effect of distances between a three car platoons, to their drag and lift coefficients, using computational fluid dynamics. To that end, a computational fluid dynamics (CFD) simulation was first performed on a single case and platoon of two Ahmed car models using the STAR-CCM+ software, for validation with previous experimental studies. Significant drop in drag coefficients were observed on platoon models compared to a single model. Comparison between the k-w and k-e turbulence models for a two car platoon found that the k-w model more closely approximate the experimental results with errors of only 8.66% compared to 21.14% by k-e turbulence model. Further studies were undertaken to study the effects of various car gaps (0.5L, 1.0L and 1.5L; L = length of the car) to the aerodynamics of a three-car platoon using CFD simulation. Simulation results show that the lowest drag coefficient that impacts on vehicle fuel savings varies depending on the car's position. For the front car, the lowest drag coefficient (CD) can be seen for car gaps corresponding to X1 = 0.5L and X2 = 0.5L, where CD = 0.1217, while its lift coefficient (CL) was 0.0366 (X1 and X2 denoting first to second and second to third car distance respectively). For the middle car, the lowest drag coefficient occurred when X1 = 1.5L and X2 = 0.5L, which is 0.1397. The lift coefficient for this car was -0.0611. Meanwhile, for the last car, the lowest drag coefficient was observed when X1 = 0.5L and X2 = 1.5L, i.e. CD = 0.263. The lift coefficient for this car was 0.0452. In this study, the lowest drag coefficient yields the lowest lift coefficient. The study also found that for even X1 and X2 spacings, the drag coefficient increased steadily from the front to the last car, while the use of different spacings were found to decrease drag coefficient of the rear car compared to the front car and had a positive impact on platoon driving and fuel-saving.

References

Y. Ko, B. Song, and Y. Oh, “Mathematical analysis of environmental effects of forming a platoon of smart vehicles,” Sustainability, vol. 11, no. 3, p. 571, 2019, doi: 10.3390/su11030571.

S. Maiti, S. Winter, and L. Kulik, “A conceptualization of vehicle platoons and platoon operations,” Transp. Res. Part C Emerg. Technol., vol. 80, pp. 1–19, 2017, doi: 10.1016/j.trc.2017.04.005.

W. Zhang, M. Sundberg, and A. Karlström, “Platoon coordination with time windows: an operational perspective,” Transp. Res. Procedia, vol. 27, pp. 357–364, 2017, doi: 10.1016/j.trpro.2017.12.129.

R. Horowitz, S. Sastry, and P. . Varaiya, “Hybrid supervisory control for modes of operation,” in Automated Vehicle and Highway Systems (AVHS), 1998.

A. Davila, E. del Pozo, E. Aramburu, and A. Freixas, “Environmental benefits of vehicle platooning,” SAE Technical Paper, 2013, doi: 10.4271/2013-26-0142.

L. Zhang, F. Chen, X. Ma, and X. Pan, “Fuel economy in truck platooning: A literature overview and directions for future research,” J. Adv. Transp., vol. 2020, pp. 1–10, 2020, doi: 10.1155/2020/2604012.

Z.-F. Yang, S.-H. Li, A.-M. Liu, Z. Yu, H.-J. Zeng, and S.-W. Li, “Simulation study on energy saving of passenger car platoons based on DrivAer model,” Energy Sources, Part A Recover. Util. Environ. Eff., vol. 41, no. 24, pp. 3076–3084, 2019, doi: 10.1080/15567036.2019.1587050.

W.-H. Hucho, “Aerodynamics of road vehicles: From fluid mechanics to vehicle engineering,” in Aerodynamics of Road Vehicles, W. Hucho, Ed. Warrendale, PA: Society of Automotive Engineers, 1998, pp. 13–26, 49–51.

M. A. Siemon, “Numerical analysis of heterogeneous and homogeneous truck platoon aerodynamic drag reduction," MSc Thesis: Auburn University, 2018.

R. Gnatowska and M. Sosnowski, “The influence of distance between vehicles in platoon on aerodynamic parameters,” EPJ Web Conf., vol. 180, p. 2030, 2018, doi: 10.1051/epjconf/201818002030.

F. H. Robertson et al., “An experimental investigation of the aerodynamic flows created by lorries travelling in a long platoon,” J. Wind Eng. Ind. Aerodyn., vol. 193, p. 103966, 2019, doi: 10.1016/j.jweia.2019.103966.

F. Browand, J. McArthur, and C. Radovich, “Fuel saving achieved in the field test of two tandem trucks, PATH Research Report UCB-ITS-PRR-2004-20,” 2004.

G. Rajamani, “CFD analysis of air flow interactions in vehicle platoons,” Postgraduate Thesis: RMIT, Australia, 2006.

P. Schito and F. Braghin, “Numerical and experimental investigation on vehicles in platoon,” SAE Int. J. Commer. Veh., vol. 5, no. 1, pp. 63–71, 2012, doi: 10.4271/2012-01-0175.

B. Daryakenari, S. Abdullah, R. Zulkifli, E. Sundararajan, and A. B. M. Sood, “Numerical study of flow over Ahmed body and a road vehicle and the change in Aerodynamic characteristics caused by rear spoiler,” Int. J. Fluid Mech. Res., vol. 40, no. 4, pp. 354–372, 2013, doi: 10.1615/interjfluidmechres.v40.i4.50.

V. L. Knoop, M. Wang, I. Wilmink, D. M. Hoedemaeker, M. Maaskant, and E.-J. Van der Meer, “Platoon of SAE level-2 automated vehicles on public roads: Setup, traffic interactions, and stability,” Transp. Res. Rec. J. Transp. Res. Board, vol. 2673, no. 9, pp. 311–322, 2019, doi: 10.1177/0361198119845885.

M. Norouzi, and M.A. Pooladi, M. Mahmoudi, and and, “Numerical investigation of drag reduction in a Class 5 medium duty truck,” J. Mech. Eng. Sci., vol. 10, no. 3, pp. 2387–2400, 2016, doi: 10.15282/jmes.10.3.2016.15.0221.

T. Han, “Computational analysis of three-dimensional turbulent flow around a bluff body in ground proximity,” AIAA J., vol. 27, no. 9, pp. 1213–1219, 1989, doi: 10.2514/3.10248.

S. R. Ahmed, G. Ramm, and G. Faltin, “Some salient features of the time-averaged ground vehicle wake,” SAE Paper 840300, 1984, doi: 10.4271/840300.

C. Hinterberger, M. Garcia-Villalba, and W. Rodi, “Large eddy simulation of flow around the Ahmed body,” in The Aerodynamics of Heavy Vehicles: Trucks, Buses, and Trains, R. McCallen, F. Browand, and J. Ross, Eds. Springer Berlin Heidelberg, 2004, pp. 77–87.

R. S. Khan and and Sudhakar Umale, “CFD aerodynamic analysis of Ahmed body,” Int. J. Eng. Trends Technol., vol. 18, no. 7, pp. 301–308, 2014, doi: 10.14445/22315381/ijett-v18p262.

I. Bayraktar, D. Landman, and O. Baysal, “Experimental and computational investigation of Ahmed body for ground vehicle aerodynamics,” SAE Technical Paper 2001-01-2742, 2001, doi: 10.4271/2001-01-2742.

M. Minguez, R. Pasquetti, and E. Serre, “High-order large-eddy simulation of flow over the ‘Ahmed body’ car model,” Phys. Fluids, vol. 20, no. 9, p. 95101, 2008, doi: 10.1063/1.2952595.

C.-H. Bruneau, E. Creusé, D. Depeyras, P. Gilliéron, and I. Mortazavi, “Coupling active and passive techniques to control the flow past the square back Ahmed body,” Comput. Fluids, vol. 39, no. 10, pp. 1875–1892, 2010, doi: 10.1016/j.compfluid.2010.06.019.

E. Serre et al., “On simulating the turbulent flow around the Ahmed body: A French-German collaborative evaluation of LES and DES,” Comput. Fluids, vol. 78, pp. 10–23, 2013, doi: 10.1016/j.compfluid.2011.05.017.

P. Madharia, M. . Tiwari, and K. Ravi, “Computational simulation of Ahmed body with varying nose radius, Ground Height & Rear Slant angle,” Int. J. Res. Appl. Sci. Eng. Technol., vol. 3, no. 5, pp. 925–932, 2015.

C.-K. Choi and D.-K. Kwon, “Wind tunnel blockage effects on aerodynamic behavior of bluff body,” Wind Struct., vol. 1, no. 4, pp. 351–364, 1998, doi: 10.12989/was.1998.1.4.351.

S. Watkins and G. Vino, “The effect of vehicle spacing on the aerodynamics of a representative car shape,” J. Wind Eng. Ind. Aerodyn., vol. 96, no. 6–7, pp. 1232–1239, 2008, doi: 10.1016/j.jweia.2007.06.042.

T.-H. Shih, W. W. Liou, A. Shabbir, Z. Yang, and J. Zhu, “A new k-ϵ eddy viscosity model for high reynolds number turbulent flows,” Comput. Fluids, vol. 24, no. 3, pp. 227–238, 1995, doi: 10.1016/0045-7930(94)00032-t.

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2021-09-19 — Updated on 2021-09-19

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[1]
H. Abdul-Rahman, H. Moria, and M. R. Mohammad Rasani, “Aerodynamic study of three cars in tandem using computational fluid dynamics”, J. Mech. Eng. Sci., vol. 15, no. 3, pp. 8228–8240, Sep. 2021.

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Vol. 15 No. 3 (2021): September 2021

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