Inclusion of the physical wind tunnel in vehicle CFD simulations for improved prediction quality

Ljungskog, Emil; Sebben, Simone; Broniewicz, Alexander

doi:10.1016/j.jweia.2019.104055

Cited by 29 publications

(9 citation statements)

References 5 publications

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“…Previous research on the aerodynamic characteristics of car with the attitude change has primarily utilized quasi-static, 9 steady-state, or wind tunnel 10 test methods. The advantage of the experiment is that it can better reflect the reality, but it is difficult to achieve because of its great limitations and high cost.…”

Section: Introductionmentioning

confidence: 99%

Research on the effect of car’s roll motion on the aerodynamic characteristics of high-speed car

Huang

Yao

Pan

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part D:

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The main purpose of this study is to study the aerodynamic mechanism of periodic roll motion of car body and provide engineering reference for car design and safety evaluation. A simplified roll motion model is established based on a real car model. The two-wheel centerline of the left-wheel symmetrical section is considered as the roll axis, and the overset mesh method was used to model the sinusoidal roll motion of the car. According to the experimental data, the frequency and maximum roll angle were set to be 10 Hz and 2.2°, respectively. A transient numerical solver based on the detached-eddy simulation method is employed. The accuracy of the numerical method is validated by means of the wind tunnel test. Due to the asymmetry of the movement, the aerodynamic change of the roll motion was obvious. It is found that the roll motion is closely related to the aerodynamic characteristics of the car. Because of the hysteresis effect, the phase of aerodynamic force on the car shifts and the most dangerous position of the car is obtained. In addition, the aerodynamic differences of the car parts are found, and the wake is analyzed in detail.

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Section: Introductionmentioning

confidence: 99%

Research on the effect of car’s roll motion on the aerodynamic characteristics of high-speed car

Huang

Yao

Pan

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part D:

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show abstract

“…Numerical studies of ground vehicles are often performed in an open-road setting to simulate more realistic vehicle operation. While there is good agreement between wind tunnel experiments and numerical simulations for the drag coefficient, there are still disparities for the lift coefficient despite correction factors that account for blockage, ground effects, and wall effects [44]. A wide-range of lift coefficient values for other configurations of the notchback DrivAer model are seen in the experimental literature.…”

Section: Lift Coefficientmentioning

confidence: 95%

Assessment of conventional and air-jet wheel deflectors for drag reduction of the DrivAer model

Nabutola

Boetcher

2021

Adv. Aerodyn.

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Aerodynamic drag is a large resistance force to vehicle motion, particularly at highway speeds. Conventional wheel deflectors were designed to reduce the wheel drag and, consequently, the overall vehicle drag; however, they may actually be detrimental to vehicle aerodynamics in modern designs. In the present study, computational fluid dynamics simulations were conducted on the notchback DrivAer model—a simplified, yet realistic, open-source vehicle model that incorporates features of a modern passenger vehicle. Conventional and air-jet wheel deflectors upstream of the front wheels were introduced to assess the effect of underbody-flow deflection on the vehicle drag. Conventional wheel-deflector designs with varying heights were observed and compared to 45∘ and 90∘ air-jet wheel deflectors. The conventional wheel deflectors reduced wheel drag but resulted in an overall drag increase of up to 10%. For the cases studied, the 90∘ air jet did not reduce the overall drag compared to the baseline case; the 45∘ air jet presented drag benefits of up to 1.5% at 35 m/s and above. Compared to conventional wheel deflectors, air-jet wheel deflectors have the potential to reduce vehicle drag to a greater extent and present the benefit of being turned off at lower speeds when flow deflection is undesirable, thus improving efficiency and reducing emissions.

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“…To ensure that reliable accuracy is achieved, it is investigated and compared against wind tunnel measurements for both the notchback and fastback DrivAer configurations for yaw angles up to 7 • . This to see if the SBES k − ω SST DSM model is an improvement compared to both DDES k − ω SST and IDDES k − ω SST, as these models have shown good correlation to measurements [93,94,95,96,97,98] and is stated as best practice for some commercial software's for automotive aerodynamic simulations.…”

Section: Reliable Accuracy: Hybrid Rans-les Modelsmentioning

confidence: 99%

Important Factors for Accurate Scale-Resolving Simulations of Automotive Aerodynamics

Ekman

2020

Linköping Studies in Science and Technology. Dissertations

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Road transports are responsible for almost 18 % of the greenhouse gas emission in Europe and are today the leading cause of air pollution in cities. Aerodynamic resistance has a significant effect on fuel consumption and hence the emission of vehicles. For electric vehicles, emissions are not affected by the aerodynamics as such but instead have a significant effect on the effective range of the vehicle.In 2017, a new measurement procedure was introduced, Worldwide Harmonized Light Vehicles Test Procedure (WLTP), for measuring emissions, fuel consumption, and range. This procedure includes a new test cycle with increased average driving speed compared to the former procedure, which thereby increases the importance of the aerodynamic resistance, as it drastically increases with speed. A second effect is that the exact car configuration sold to the customer needs to be certified in terms of fuel consumption and emissions. The result is that every possible combination of optional extras, which might affect the aerodynamic resistance, needs to be aerodynamically analyzed and possibly improved. From 2021, the European Commission will introduce stricter emission regulations for new passenger cars, with the fleet-wide average lowered to 95 grams CO 2 /km, which puts an even higher demand on achieving efficient aerodynamics.

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Inclusion of the physical wind tunnel in vehicle CFD simulations for improved prediction quality

Cited by 29 publications

References 5 publications

Research on the effect of car’s roll motion on the aerodynamic characteristics of high-speed car

Research on the effect of car’s roll motion on the aerodynamic characteristics of high-speed car

Assessment of conventional and air-jet wheel deflectors for drag reduction of the DrivAer model

Important Factors for Accurate Scale-Resolving Simulations of Automotive Aerodynamics

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