Investigation of vehicle ride height and wheel position influence on the aerodynamic forces of ground vehicles

Vdovin, Alexey; Sebben, Simone; Walker, Tim; Löfdahl, Lennart

doi:10.1533/9780081002452.3.81

Cited by 7 publications

(8 citation statements)

References 7 publications

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“…Even with the slight discrepancies described taken into account, the additional vertical displacement in most cases still lies in the range of 4 to 6 millimeters, which corresponds well with the data obtained by Vdovin [7], where the vertical displacement due to tire radial expansion for a relevant velocity of 140 kph is around 5 millimeters for both axles. It can therefore be concluded that the phenomenon in question can be held responsible for the fact that ride heights experienced by a car on the road are significantly higher than expected when only taking into account aerodynamic loading.…”

Section: Resultssupporting

confidence: 88%

“…As shown, for example, by Regert [8], the aerodynamic drag of a vehicle decreases as the wheel diameter in a wheel housing of constant shape increases. This was also confirmed by Vdovin [7], who stated that with the vertical position of the body fixed, increasing velocities, i.e. increasing wheel diameter, cause the drag of the vehicle to decrease compared to the case where vertical displacement is allowed.…”

Section: Shrnutísupporting

confidence: 55%

“…Further work has been done by Vdovin [7], who designed "floating struts" to allow for vertical travel of a vehicle body in a wind tunnel while still holding the car in position. By measuring the front and rear ride heights at several velocities with the tunnel fan switched on and off (wheels were rotating in all cases), he demonstrated that the radial expansion of the tires indeed forces the vehicle to rise (see Figure 3).…”

Section: Shrnutímentioning

confidence: 99%

“…Comparison of front and rear vehicle body lifts in the wind tunnel with wind on and off [7]. OBRÁZEK 3: Srovnání zvedání přední a zadní části karoserie v aerodynamickém tunelu se zapnutým a vypnutým ventilátorem [7].…”

Section: Figureunclassified

“…OBRÁZEK 3: Srovnání zvedání přední a zadní části karoserie v aerodynamickém tunelu se zapnutým a vypnutým ventilátorem [7].…”

Section: Figureunclassified

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Vehicle Ride Height Change Due To Radial Expansion Of Tires

Čavoj¹,

Blaťák²,

Hejtmánek³

et al. 2015

Journal of Middle European Construction and Design of Cars

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In general, tire deformations caused by wheel rotation are not taken into account when developing vehicle aerodynamics. On the road the tires radially expand as speed increases, which affects the actual ride height of a vehicle. In turn this often increases the real aerodynamic drag compared to values obtained using CFD or a wind tunnel as the mass flow across the relatively rough underbody increases with ground clearance. In this study, on-road ride heights were measured while running a vehicle in a straight line with fixed velocity whilst the aerodynamic lift of the vehicle was determined in a wind tunnel. Subsequently, the relationships between ride height and axle load were obtained by loading the vehicle at standstill with ballast. By comparing the ride heights at high and very low velocities with expected vertical displacement caused purely by aerodynamic lift force as computed according to the ride height -axle load equations, the ride height change due to tire radial expansion was determined.

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Section: Resultssupporting

confidence: 88%

Section: Shrnutísupporting

confidence: 55%

Section: Shrnutímentioning

confidence: 99%

Section: Figureunclassified

“…OBRÁZEK 3: Srovnání zvedání přední a zadní části karoserie v aerodynamickém tunelu se zapnutým a vypnutým ventilátorem [7].…”

Section: Figureunclassified

See 3 more Smart Citations

Vehicle Ride Height Change Due To Radial Expansion Of Tires

Čavoj¹,

Blaťák²,

Hejtmánek³

et al. 2015

Journal of Middle European Construction and Design of Cars

View full text Add to dashboard Cite

show abstract

The influence of spoiler on the aerodynamic performances and longitudinal stability of the passenger car under high speed condition

Stojanović

Abdullah

Grujić

et al. 2022

J Vis

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Influence of rotating wheels on Reynolds number sensitivity of passenger vehicle drag

Josefsson,

Urquhart,

Sebben

2024

Physics of Fluids

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Rotating wheels are essential to replicate realistic forces and flow fields during aerodynamic testing of passenger vehicles. Previous studies have found that the drag coefficient typically reduces with increased speed under rotating wheel conditions but is stable with stationary wheels. This paper investigates this velocity sensitivity for two vehicles, the aerodynamic research vehicle DrivAer and a production vehicle. Experiments with the DrivAer indicate that the drag reduction with increased speed cannot be explained by pressure changes on the vehicle body; instead, the effect is attributed to local flow changes around the wheels. Using numerical simulations, it is found that the separation at the front wheels' outer tire shoulder increases for lower velocities, thus resulting in higher drag coefficient and causing Reynolds number sensitivity. The degree of drag reduction is less for the DrivAer squareback than for the notchback due to the separation over the notchback's rear window. No direct difference is measured between various tires and rims. To assess the generality of the findings with the DrivAer, the results are compared to experiments with a production vehicle. It is observed that the drag sensitivity is less and only occurs if the rear wheels are rotating. Pressure measurements in the wheelhouses and around the wheel drive units confirm the front wheel separation's dependence on velocity and highlight the complex interaction between the front wheel wakes and rear wheel rotational state.

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Investigation of vehicle ride height and wheel position influence on the aerodynamic forces of ground vehicles

Cited by 7 publications

References 7 publications

Vehicle Ride Height Change Due To Radial Expansion Of Tires

Vehicle Ride Height Change Due To Radial Expansion Of Tires

The influence of spoiler on the aerodynamic performances and longitudinal stability of the passenger car under high speed condition

Influence of rotating wheels on Reynolds number sensitivity of passenger vehicle drag

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