Aerodynamics of electric cars in platoon SAGE publications

Ebrahim, Hesham; Dominy, Robert; Martin, Nick

doi:10.1177/0954407020965028

Cited by 10 publications

(5 citation statements)

References 15 publications

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“…These observations contradict the slip-streaming effect as it is commonly understood, however, it agrees with remarks made by other researchers on platoons of vehicles in pairs [5,7,8,13,16,23,31]. This suggests that the slip-streaming effect is not universal and is highly dependent on the chosen geometry and distance between these geometries, which may help explain the misconceptions associated with this term.…”

Section: Overall Analysissupporting

confidence: 79%

“…Velocity and pressure contours were not provided in this manuscript as the observations made were largely similar to those reported in [5,7], which explains the fundamental reasons a trailing vehicle exhibits a drag increase in certain arrangements and spacing. In addition, due to the bespoke nature of this investigation, no experimental research data was found to compare this dataset.…”

Section: Two-vehicle Platoonmentioning

confidence: 87%

“…The concept of passenger cars operating in low drag platoons is well established (e.g., [1,2]), but it has been recent developments in inter-vehicle communication and smart/autonomous vehicle (AV) capability that have brought the concept closer to reality. Almost all major manufacturers expect to bring such vehicles to the market within the next few years [3,4] and the development of platooning has gained impetus by its potential to increase the range of electric vehicles that will eventually dominate the market [5].…”

Section: Introductionmentioning

confidence: 99%

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The Effect of Afterbody Geometry on Passenger Vehicles in Platoon

Ebrahim¹,

Dominy

2021

Energies

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It is well known that platoons of closely spaced passenger cars can reduce their aerodynamic drag yielding substantial savings in energy consumption and reduced emissions as a system. Most published research has focused on platoons of identical vehicles which can arguably be justified by some evidence that geometric variety has little to no effect on the overall flow characteristics in platoons of three vehicles or more. It is known that much of the aerodynamic benefit from platooning is gained by the leading two cars, so operating as vehicle pairs could potentially achieve similar environmental benefits whilst addressing many of the practical challenges associated with the safe operation of long platoons on public roads. However, it has been reported that unlike long platoons, the effect of geometry and arrangement is critical if the drag reduction of a pair is to be optimised. This paper describes a parametric study based on three geometric variants of the popular DrivAer model with different combinations and spacings. It is confirmed that vehicle geometry crucially affects the results with the best combinations matching those of long platoons and others creating a net drag increase.

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Section: Overall Analysissupporting

confidence: 79%

Section: Two-vehicle Platoonmentioning

confidence: 87%

Section: Introductionmentioning

confidence: 99%

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The Effect of Afterbody Geometry on Passenger Vehicles in Platoon

Ebrahim¹,

Dominy

2021

Energies

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“…k-turbulent energy, ε-dissipation rate, vl & vt laminar and turbulent kinematic viscosities [14][15][16].…”

Section: Energy Dissipation Equationmentioning

confidence: 99%

Numerical Study on Low Speed Electric Car for Public Transportation to Predict Its Aerodynamic Performance and Stability

Mamo

Gopal

Yoseph

et al. 2023

ETJ

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Energy efficiency and dynamic stability of Battery Electric Vehicle (BEV) is highly influenced by size of powertrain, aerodynamic characteristics and driving conditions. The main idea of this work was to study aerodynamic performance of BEV sized based on Ethiopian driving profile and BAJAJ QUTE chassis platform. Numerical analysis was conducted to reveal various surface features and side wind velocities influence using coefficients of aerodynamic forces and moments, vector and contour plots of CFD (Computational Fluid Dynamics). From the analysis, it was found that average aerodynamic coefficients and moments with side wind are much higher than simulated values of original car with corresponding values of CD (3.11), CL (0.45), YM (-240.52Nm) and RM (-363.84Nm). The power requirement to overcome aerodynamic road load with 10m/sec side wind has increased (13.36kW) by 3.3 times as compared to no wind effect power of (4.05kW). The car moving through a straight level road found to be stable at any side-wind below 15m/sec, but it could reach to unstable condition in curved road. For car moving in any road under side-wind greater than 15m/s, there is a chance of turnover and breakaway of a lane.

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“…They then continued the work into CFD simulation of heavily simplified automotive body, finding that the k − model was able accurately predict the intake of pollutants. Ebrahim et al [11] used the Realizable k − model to compare CFD results of electric passenger vehicle platoons to data gathered through track testing and found that the Realizable k − was not able to predict the drag on the vehicles with great accuracy, leading to a large discrepancy between the calculated power usage of the vehicles and the actual. A notable CFD work in the study of drafting is Pagliarella [12] who performed wind tunnel testing on a variety of slant angles, determining that the vortices created from the rear of the lead Ahmed body were impinged upon by the trailing body.…”

Section: Introductionmentioning

confidence: 99%

Development of a Numerical Investigation Framework for Ground Vehicle Platooning

Bounds

Rajasekar

Uddin

2021

Fluids

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This paper presents a study on the flow dynamics involving vehicle interactions. In order to do so, this study first explores aerodynamic prediction capabilities of popular turbulence models used in computational fluid dynamics simulations involving tandem objects and thus, ultimately presents a framework for CFD simulations of ground vehicle platooning using a realistic vehicle model, DrivAer. Considering the availability of experimental data, the simulation methodology is first developed using a tandem arrangement of surface-mounted cubes which requires an understanding on the role of turbulence models and the impacts of the associated turbulence model closure coefficients on the prediction veracity. It was observed that the prediction accuracy of the SST k−ω turbulence model can be significantly improved through the use of a combination of modified values for the closure coefficients. Additionally, the initial validation studies reveal the inability of the Unsteady Reynolds-Averaged Navier-Stokes (URANS) approach to resolve the far wake, and its frailty in simulating tandem body interactions. The Improved Delayed Detached Eddy Simulations (IDDES) approach can resolve the wakes with a reasonable accuracy. The validated simulation methodology is then applied to the fastback DrivAer model at different longitudinal spacing. The results show that, as the longitudinal spacing is reduced, the trailing car’s drag is increased while the leading car’s drag is decreased which supports prior explanations of vortex impingement as the reason for drag changes. Additionally, unlike the case of platooning involving Ahmed bodies, the trailing model drag does not return to an isolated state value at a two car-length separation. However, the impact of the resolution of the far wake of a detailed DrivAer model, and its implication on the CFD characterization of vehicle interaction aerodynamics need further investigations.

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Aerodynamics of electric cars in platoon SAGE publications

Cited by 10 publications

References 15 publications

The Effect of Afterbody Geometry on Passenger Vehicles in Platoon

The Effect of Afterbody Geometry on Passenger Vehicles in Platoon

Numerical Study on Low Speed Electric Car for Public Transportation to Predict Its Aerodynamic Performance and Stability

Development of a Numerical Investigation Framework for Ground Vehicle Platooning

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