Computational aero-acoustic analysis of a passenger car with a rear spoiler

Tsai, Chien Hsiung; Fu, Lung-Ming; Tai, Chang-Hsien; Huang, Y.-L.; Leong, Jik Chang

doi:10.1016/j.apm.2008.12.004

Cited by 44 publications

(27 citation statements)

References 10 publications

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“…Configurations C and D exhibit an increased C D when compared to configurations A and B due to the front and rear wings. This is in good agreement with the results reported in [5], [16]. The maximal C D equal to 0.88 is observed in configuration D, indicating that the 3EL wing has a higher value of drag force for the same overall chord length and the same wind incidence angle when compared to the 2EL wing.…”

Section: Resultssupporting

confidence: 82%

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Aerodynamic Performance of the Underbody and Wings of an Open-Wheel Race Car

2016

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SummaryBasic aerodynamic characteristics of a generic open-wheel race car equipped with various aerodynamic devices are studied. The focus is on the influence of car underbody design and the front and rear wings on aerodynamic forces experienced by the car. Computational simulations are carried out assuming the steady viscous fluid flow and using the Reynolds-averaged-Navier-Stokes equations and the standard shear stress transport (SST) k-ω turbulence model. The lift force in the configuration with a flat car underbody (without a rear diffuser at the trailing edge of the car underbody) and without the wings is positive (undesirable upforce), while a negative lift force (favourable downforce) is obtained in all configurations with aerodynamic devices (underbody rear diffuser, front wing, rear wing). The aerodynamic devices create an increased, undesirable drag force in comparison with the configuration without the aerodynamic devices. The downforce and the drag force are similar when wings consisting of two and three elements are used. This indicates that, for the same overall chord and wind incidence angle, the number of wing elements is not a very important factor influencing the aerodynamic loads experienced by this type of open-wheel race car with a similar front and rear wing layout. The optimal configurations with respect to the lift-to-drag ratio are those with the rear diffuser and wings in place. In the configuration with threeelement wings, streamlines in the region of the rear wing are analysed both computationally and experimentally using the tuft flow technique. Good agreement between the computational and limited experimental results regarding streamlines is achieved. However, this would need to be further analysed quantitatively in order to fully validate the developed computational model. Key words:Race car aerodynamics, car underbody and wings, computational simulations, field experiments. IntroductionRace cars can experience extreme aerodynamic loads during the race due to various devices designed to optimize the race car aerodynamics, e.g. rear diffuser at the trailing edge of the car underbody as well as the front and rear wings on the car body [1]. The main focus is on enhancing the aerodynamic downforce that generally improves the car traction and stability, while simultaneously trying to avoid a considerable increase in the drag force as it Aerodynamic properties of passenger and race cars are commonly studied experimentally in wind tunnels, but significant efforts are made in the computational fluid dynamics in order to improve its reliability and accuracy for that purpose [3]. Therefore, the development of car aerodynamics nowadays commonly combines wind-tunnel experiments, field measurements and computational simulations.Reference [4] points out the importance of improving the cornering ability of race cars. Aerodynamic devices have been developed for the Formula SAE car, with a special focus on the rear diffuser, and the front and rear wings, as reported in [5]. The flow field around th...

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Section: Resultssupporting

confidence: 82%

“…[16][17]. Increase in the rear diffuser angle with respect to the ground surface can decrease an adverse upforce [18].…”

Section: Introductionmentioning

confidence: 99%

Aerodynamic Performance of the Underbody and Wings of an Open-Wheel Race Car

2016

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“…Note that this positive combination -reduction in both the drag and lift -is highly appreciable as it is often the case that the element that increases the downforce will also increase drag (e.g. [2][3][4]). …”

Section: Effects Of Rear Spoiler Anglementioning

confidence: 99%

“…The effectiveness of wing-type spoiler has been reported in numerous studies. For instance, Tsai et al [2] investigated numerically five different spoiler configurations. The spoilers are of inverted airfoil type and were mounted on the trunk of a simplified car model based on the HONDA S2000.…”

Section: Introductionmentioning

confidence: 99%

Influence of rear-roof spoiler on the aerodynamic performance of hatchback vehicle

Cheng

Mansor

2016

MATEC Web Conf.

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Abstract. Rear-roof spoiler is commonly used for improving the aerodynamic performance of road vehicles. This study aims to investigate the effect of strip-type rear-roof spoiler on the aerodynamic performance of hatchback vehicles. The main parameter of study was the inclination angle of the spoiler. A computational fluid dynamics (CFD) method was used. The numerically obtained results were compared to the experimental data for validation of the CFD method. The spoiler effectively reduced the aerodynamic lift at positive inclination angle by causing the surface pressure near the roof-spoiler junction to increase. However, its effect is unfavourable when configured at negative angle due to the downward accelerating flow that causes the surface pressure around the roof-spoiler junction to drop. Although the aerodynamic lift was found to decrease with the spoiler angle, this was accompanied by drag increment.

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“…Tsai et al [13] investigated the flow structures and aero-acoustic features generated in the various rear spoiler configurations of a passenger car, using computational flow dynamics. In another study, Kieffer et al simulated a turbulent flow around the front and rear wing of a Formula Mazda race car and analyzed the effect of their angle of attack on car handling [14].…”

Section: Introductionmentioning

confidence: 99%

Fluid-structure interaction analysis of rear spoiler vibration for energy harvesting potential

Rasani¹,

Aldlemy

Harun³

2017

J. MECH. ENG. SCI.

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Increasing environmental and energy concerns constitutes an encouraging development of future automobiles and autonomous vehicles that utilize cleaner and renewable energy. Although primarily an aerodynamic device, car rear spoilers experience various vibrations and limited attention has been given to exploiting these vibrations for generating alternative energy. This paper aims to investigate the potential of using the flow-induced vibration of rear spoilers on automobiles for energy harvesting. To that end, a fluid-structure interaction analysis of an inverted NACA 2408 spoiler behind an Ahmed body was undertaken. An Arbitrary Lagrangian-Eulerian flow solver was coupled to a non-linear structural dynamic solver using a commercial software application. The vibrations of the rear spoiler placed at 0, 50 and 100 mm below the top face of the Ahmed body under Reynolds number Re = 2.7 × 10 6 were simulated. It was found that the vibration of the rear spoiler at the highest elevation showed the largest amplitudes and strain, but the vibration of the rear spoiler at the lowest elevation offers an extended period of vibration before reaching a steady state. With the rear spoiler positioned at the highest elevation, a vibration frequency of 70 Hz and a steady-state principal strain of 350  may be achieved. These vibration levels compared well with previous investigation to sufficiently charge storage capacitors for wireless transmitters. The rear spoiler vibration may offer potential means for energy harvesting, and warrants further experiments under actual driving conditions.

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Computational aero-acoustic analysis of a passenger car with a rear spoiler

Cited by 44 publications

References 10 publications

Aerodynamic Performance of the Underbody and Wings of an Open-Wheel Race Car

Aerodynamic Performance of the Underbody and Wings of an Open-Wheel Race Car

Influence of rear-roof spoiler on the aerodynamic performance of hatchback vehicle

Fluid-structure interaction analysis of rear spoiler vibration for energy harvesting potential

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