Aerodynamic Characteristics of a Road Vehicle in Steady-State Cornering

Nakashima, Takuji; Tsubokura, Makoto; Okada, Yoshihiro; Nouzawa, Takahide; Kono, Ryosuke; Doi, Yoshihiro

doi:10.1115/ajkfluids2015-17553

Cited by 4 publications

(2 citation statements)

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“…In work by Nakashima et al [3], results of measurements performed in a pool with a controlled motion of the Ahmed model during a turn were presented. In the next work of Nakashima et al [4], the motion of a car through a curve was studied experimentally in a water tunnel and numerically. The authors assumed that the curved motion of the vehicle could be treated as the superposition of circular motion with rotation about the center of gravity and rectilinear motion with oblique body alignment.…”

Section: Introductionmentioning

confidence: 99%

Influence of the Car Movable Aerodynamic Elements on Fast Road Car Cornering

et al. 2022

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In the case of road cars, road safety is the primary factor. The geometry of high-speed road cars has no regulatory restrictions. In addition to the high engine power and effective shape, they can use various types of additional movable aerodynamic elements to adjust their aerodynamic characteristics to the road conditions. Based on the geometry of a two-seater prototype of such a vehicle, a numerical analysis of the influence of a number of additional movable aerodynamic elements on its aerodynamic characteristics was performed. Several of them were installed on the prototype. An electronic system recording a number of motion parameters of the entire car body and some of its movable elements installed on the body was designed and built. The system has been adapted to program the motion of additional aerodynamic elements according to the set algorithms of their activation, temporarily changing the aerodynamic characteristics of the car. An experimental study of the effect of changes in the aerodynamic characteristics of the prototype on its dynamic properties during a drive through a test road section was carried out. It was shown to what extent an average driver can increase the safe speed of the curve of the road using the possibilities of moving aerodynamic elements installed on it.

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Section: Introductionmentioning

confidence: 99%

Influence of the Car Movable Aerodynamic Elements on Fast Road Car Cornering

et al. 2022

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“…This characteristic is also suitable for the fluid dynamics measurement of a vehicle during cornering motion because the cornering motion is an accelerating motion in the lateral direction of the vehicle. In our previous research [26,27], the fluid-dynamic force acting on a one-fifth-scale model of a sedan-type automobile during steady-state cornering was measured in a towing tank facility. These measurements clarified the characteristics of the side force and yaw moment, which were similar to those with a simplified model [13], focusing on the aerodynamic effects on the drivability.…”

Section: Introductionmentioning

confidence: 99%

Fluid-Dynamic Force Measurement of Ahmed Model in Steady-State Cornering

et al. 2020

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The effects of on-road disturbances on the aerodynamic drag are attracting attention in order to accurately evaluate the fuel efficiency of an automobile on a road. The present study investigated the effects of cornering motion on automobile aerodynamics, especially focusing on the aerodynamic drag. Using a towing tank facility, measurements of the fluid-dynamic force acting on Ahmed models during steady-state cornering were conducted in water. The investigation included Ahmed models with slant angles θ = 25° and 35°, reproducing the wake structures of two different types of automobiles. The drag increase due to steady-state cornering motion was experimentally measured, and showed good agreement with previous numerical research, with the measurements conducted at a Reynolds number of 6 × 105, based on the model length. The Ahmed model with θ = 35° showed a greater drag increase due to the steady-state cornering motion than that with θ = 25°, and it reached 15% of the total drag at a corner with a radius that was 10 times the vehicle length. The results indicated that the effect of the cornering motion on the automobile aerodynamics would be more important, depending on the type of automobile and its wake characteristics.

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A Theoretical and Experimental Investigation of the Effects of Inverted Wings Modifications on the Stability and Aerodynamic Performance of a Sedan Car at Cornering

Abood,

Hussain,

Ali

2024

Engineering Reports

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This research examines the impact of cornering on the aerodynamic forces and stability of a Nissan Versa (Almera) passenger sedan car by introducing novel modifications. These modifications included single inverted wings with end plates as a front spoiler, double‐element inverted wings with end plates as a rear spoiler, and incorporating the ground as a diffuser under the car trunk. The goal is to enhance the performance and stability of conventional passenger cars. To ensure the accuracy of the numerical data, the study utilized multiple methodologies to model the turbulence model, ultimately selecting the most suitable option. This involved comparing numerical data with wind tunnel experimental data using force balance and pressure distribution. Once validated, the computational fluid dynamics (CFD) was employed to analyze the vehicle's aerodynamic performance relative to the straight‐line condition under cornering conditions. The car simulation in a cornering condition was conducted at a representative Reynolds number based on the vehicle length of about 1.3 × 107. The study discovered that asymmetry was a recurring theme regarding surface pressure distribution, with greater prominence under cornering conditions. All modified models exhibited a more favorable lift‐to‐drag ratio than the baseline, indicating improved aerodynamic efficiency. The underbody double‐element diffuser proved most effective for enhancing fuel efficiency and stability. Mesh refinement with a polyhedral algorithm consisting of 11.27 million elements and a computational domain with a frontal area of 91.8 m2 and a curved length of 31 m (˜7 times car length) was crucial for achieving accurate and repeatable results. The study employed multiple turbulence models within the CFD framework. The realizable k‐ε model was chosen due to its balance between accuracy and computational cost for all Nissan Versa models. These findings are limited to the selected parameters and wind tunnel conditions, and further investigations might be needed for extreme driving scenarios.

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Aerodynamic Characteristics of a Road Vehicle in Steady-State Cornering

Cited by 4 publications

References 0 publications

Influence of the Car Movable Aerodynamic Elements on Fast Road Car Cornering

Influence of the Car Movable Aerodynamic Elements on Fast Road Car Cornering

Fluid-Dynamic Force Measurement of Ahmed Model in Steady-State Cornering

A Theoretical and Experimental Investigation of the Effects of Inverted Wings Modifications on the Stability and Aerodynamic Performance of a Sedan Car at Cornering

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