Numerical Investigation of the Flow Around a Simplified Ground Vehicles Using Hybrid RANS/LES Method

Delassaux, Francois; Herbert, Vincent; Mortazavi, Iraj; Ribes, Charles

doi:10.1007/978-3-030-27607-2_29

Cited by 3 publications

(2 citation statements)

References 21 publications

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“…2. The stable value of the aerodynamic drag coefficient was about 8.1% smaller than the experimental value, which was reasonable for this turbulent model (Delassaux et al 2020). The counterpart for CL was 8.3%, but less than 10%.…”

Section: Grid Independence Verificationsupporting

confidence: 69%

Coupled Analysis of Transient Aerodynamic Characteristics of the Coach under Crosswind in Different Situations

2021

JAFM

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The purpose of this work is to investigate transient aerodynamic characteristics of the coach under the crosswind in straight-line situations with different uniform speeds and uniform accelerations. The transient aerodynamics caused by different speed changes are analyzed using the real-time interaction between aerodynamic simulation and dynamic simulation. The target model is a simplified coach on a full scale. The SST (Menter) K-Omega Improved Delayed Detached Eddy Simulation and overset mesh technique are used to predict the transient aerodynamic loads. The accuracy of the turbulence model is verified by a wind tunnel experiment of the 1/7th scaled coach model. The present results show that the transient aerodynamic loads have different locations of maximum side force and the holding duration of yaw moment for different constant speeds. The speed becomes larger, and the position where the side force is maximum becomes farther away. The holding duration of the top yaw moment is larger simultaneously. Moreover, proper acceleration for low initial driving speed and crosswind of small influence range could build up stability. High speed driving in gust wind is not suggested for unskilled drivers.

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Section: Grid Independence Verificationsupporting

confidence: 69%

Coupled Analysis of Transient Aerodynamic Characteristics of the Coach under Crosswind in Different Situations

2021

JAFM

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“…However, for vehicle platoon, the flow structure between vehicles is more complex at closer distances. For the three-dimensionality and instability of this turbulence, the RANS model is difficult to predict, and this phenomenon was also shown in their research (Delassaux et al , 2019; Guilmineau et al , 2018; Hinterberger et al , 2004; Kapadia et al , 2004; Luo et al , 2022).…”

Section: Selection and Validation Of Numerical Simulation Methodsmentioning

confidence: 96%

Aerodynamic optimization of mixed platoon Ahmed body vehicles based on response surface method

Luo,

Tie,

et al. 2023

HFF

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Purpose The purpose of this paper is to investigate the optimal average drag coefficient of the Ahmed body for mixed platoon driving under crosswind and no crosswind conditions using the response surface optimization method. This study has extraordinary implications for the planning of future intelligent transportation. Design/methodology/approach First, the single vehicle and vehicle platoon models are validated. Second, the configuration with the lowest average drag coefficient under the two conditions is obtained by response surface optimization. At the same time, the aerodynamic characteristics of the mixed platoon driving under different conditions are also analyzed. Findings The configuration with the lowest average drag coefficient under no crosswind conditions is 0.3 L for longitudinal spacing and 0.8 W for lateral spacing, with an average drag coefficient of 0.1931. The configuration with the lowest average drag coefficient under crosswind conditions is 10° for yaw angle, 0.25 L for longitudinal spacing, and 0.8 W for lateral spacing, with an average drag coefficient of 0.2251. Compared to the single vehicle, the average drag coefficients for the two conditions are reduced by 25.1% and 41.3%, respectively. Originality/value This paper investigates the lowest average drag coefficient for mixed platoon driving under no crosswind and crosswind conditions using a response surface optimization method. The computational fluid dynamics (CFD) results of single vehicle and vehicle platoon are compared and verified with the experimental results to ensure the reliability of this study. The research results provide theoretical reference and guidance for the planning of intelligent transportation.

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Investigation of the Aerodynamic Characteristics of Platoon Vehicles Based on Ahmed Body

Luo

Tan

et al. 2022

Shock and Vibration

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In this paper, the aerodynamic characteristics of two vehicles and three vehicles in the platoon under different vehicle spacings have been explored in detail. Firstly, the realizable k- ε model was used to verify the numerical method based on a single 35° Ahmed body. Then, the aerodynamic characteristics such as drag characteristics, surface pressure, wake structure, and turbulent kinetic energy distribution were analyzed for the platoon of two and three 35° Ahmed bodies. Although the RANS (Reynolds-averaged Navier–Stokes) model had got good results for simulating a single 35° Ahmed body, when simulating two 35° Ahmed bodies in the platoon, it was found that there is still a big error compared with the experimental data. In the three 35° Ahmed body, the drag coefficient of the leading body is almost unchanged compared with that of the leading body in the two-vehicle platoon, while the drag coefficients of the middle body and the trailing body are both reduced compared with those of the single body. For x/L = 0.25, the middle body is about 56% of the single-body value, and the trailing car is about 88% of the single-body value. It can be seen that the drag reduction effect of three 35° Ahmed bodies is larger than that of two 35° Ahmed bodies. It is shown that the aerodynamic characteristics are very sensitive to the selected platoon vehicle model. Because model with different geometric shapes will produce different wake structures, different aerodynamic phenomena will occur when they are arranged in the platoon.

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Numerical Investigation of the Flow Around a Simplified Ground Vehicles Using Hybrid RANS/LES Method

Cited by 3 publications

References 21 publications

Coupled Analysis of Transient Aerodynamic Characteristics of the Coach under Crosswind in Different Situations

Coupled Analysis of Transient Aerodynamic Characteristics of the Coach under Crosswind in Different Situations

Aerodynamic optimization of mixed platoon Ahmed body vehicles based on response surface method

Investigation of the Aerodynamic Characteristics of Platoon Vehicles Based on Ahmed Body

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