Salient drag reduction of a heavy vehicle using modified cab-roof fairings

Kim, Jeong Jae; Lee, Sang-Seung; Kim, Myeongkyun; You, Donghyun; Lee, Sang Joon

doi:10.1016/j.jweia.2017.02.015

Cited by 43 publications

(16 citation statements)

References 17 publications

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“…The ground transportation system (GTS) model is a simplified cab-over-engine truck model and is representative of a tractor-trailer combination without any intermediate gap. The earliest experimental investigations of the GTS model by [10] and [71] were performed with the aim of reducing drag by the use of active and passive flow control devices (several addon devices such as slanted rear end and boat-tails to the base of the model) ( [4,8,9,14,28,44,47,54], and others). Storms et al [71] reported a 19% reduction in the drag coefficient by the use of boat-tail plates.…”

Section: Introductionmentioning

confidence: 99%

An LES Investigation of the Near-Wake Flow Topology of a Simplified Heavy Vehicle

Rao

Zhang

Minelli

et al. 2018

Flow Turbulence Combust

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Recent experimental investigations by McArthur et al. (J. Fluids Struct. 66, 293-314, 2016) in the wake of a simplified heavy vehicle or commonly known as the ground transportation system (GTS) model has shown that the flow topology is invariant over a large range of Reynolds numbers [2.7 × 10 4 − 2 × 10 6 ]. Numerical simulations are performed to investigate the initial flow topology at a Reynolds number of 2.7 × 10 4 , using well-resolved large eddy simulations (LES). In the vertical midplane behind the GTS, a flow state which is anti-symmetric to that reported in McArthur et al. (J. Fluids Struct. 66, 293-314, 2016) is observed here, thereby, confirming the possibility of occurrence of the complementary bi-stable flow state. The occurrence of this bi-stable state does not depend on the ground clearance between the GTS and the ground plane, as a similar flow topology is observed at both small and large gap heights. Furthermore, the flow topology in the vertical midplane is also found to be insensitive to the incoming flow for small yaw angles. However, complex flow behaviour is observed in the wake for larger yaw angles, where the flow topology in the vertical midplane becomes nearly symmetric, while an asymmetric flow topology is now observed in the lateral midplane in the near wake. Furthermore, the corner vortices which originate from either side at the front of the model merge in the far wake, leading to a large vortex structure nearly equal to the height of the model. The near-wake topology of the GTS is analysed and compared with previous studies for a range of scenarios, and the forces on the GTS are computed.

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Section: Introductionmentioning

confidence: 99%

An LES Investigation of the Near-Wake Flow Topology of a Simplified Heavy Vehicle

Rao

Zhang

Minelli

et al. 2018

Flow Turbulence Combust

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“…For a tractor-trailer driving on a highway, the front part of the vehicle causes approximately 45% of the total drag force; the other contributing factors include the rear wake of the trailer (25%) and the underbody flow (30%) [10]. Corresponding research was carried out at different positions, and various kinds of drag-reducing devices have been introduced to effectively decrease the aerodynamic drag of tractor-trailers, including their cab roofs or gap fairings [11][12][13][14], their side skirts [15], their base flaps [16], and their boat tails [17,18]. Some studies focused on their aerodynamic characteristics, using a combination of various devices and interactions with the actual complex shape of tractor-trailers [19,20].…”

Section: Introductionmentioning

confidence: 99%

Research on the Aerodynamic Characteristics of Tractor-Trailers with a Parametric Cab Design

et al. 2018

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As tractor-trailer ownership has increased year-by-year, corresponding energy consumption and environmental issues have gradually become a heated issue. Approximately 45 percent of the total aerodynamic drag of tractor-trailers is attributed to the flow at the front surface of the cab, and the gap between the cab and trailer. Therefore, this study has taken a new approach to designing the shape of the cab inspired by the external forebody of the cheetah. A parametric design protruding cab was devised in this study; the length of the protruding part and the angle between this protruding part and the A pillar were two design variables. Computational fluid dynamics simulation was conducted to investigate the drag reduction effects of these new cab styling designs, and the proposed cab reduced the drag by a maximum of 8.49%. The flow characteristics around the whole body of the tractor-trailer baseline model and the parametric cab design vehicle model were analyzed using the velocity streamline graph to illuminate the change of the flow field and the drag-reduction mechanism of the proposed design. A vortex formed above the protruding part of the cab and it acted as a 'vortex cushion' to accelerate the speed of the air flow; accordingly, the positive and negative pressure distribution on the front surface of the cab and trailer also changed. The new parametric design has provided the possibility to adjust the forebody of the cab to an aerodynamically optimized shape, and these findings have offered useful information for the development of a new design method of the tractor-trailer to reduce aerodynamic drag and improve fuel economy.

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“…Pflug [10] conducted 3D simulations how different combinations of tractor and trailer change in lateral stability, damping performance and vibration frequency, under extreme driving conditions. Kim et al [11] disclosed the mechanism of drag reduction by analyzing the precursor of the vehicle model, laying the basis for the design of new conditional random field (CRF) models and the improvement of aerodynamic performance of heavy vehicles.…”

Section: Relevant Studies On the D-p Transportmentioning

confidence: 99%

“…Formula (9) indicates that the trailers from a supply point can only travel through the same freight station; Formula (10) specifies that the trailers to a demand point should come from the same freight station; Formula (11) regulates that the total quantity of goods on the trailers arriving at freight station j should not surpass the capacity of that station; Formula (12) requires that the number of trailers from freight station j to demand point k must satisfy the demand at that point; Formula (13) means the number of trailers entering a freight station should equal that leaving the station; Formula (14) ensures that the parameters are nonnegative.…”

Section: Symbols and Decision Variablesmentioning

confidence: 99%

Optimization of Drop-and-Pull Transport Network Based on Shared Freight Station and Hub-and-Spoke Network

Feng¹,

Cheng²

2019

JESA

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The current drop-and-pull (D-P) transport process has many defects, including but not limited to the insufficient information sharing, the private ownership of vehicles and infrastructure, and the mismatch between vehicles and goods. Moreover, the hardware and software of existing freight stations fall short of the demand for D-P transport. To solve these problems, this paper optimizes the design of the D-P transport network based on shared freight station and the hub-and-spoke (H-S) network. The freight stations were taken as the hubs, and the routes between supply/demand point and freight station are treated as spokes. On this basis, an optimization model was established to minimize the total cost of freight stations and maximize the force from freight stations on supply/demand points in the H-S D-P network. In addition, all the supply/demand points in the region are covered by the selected freight stations. The LINGO software was introduced to solve the established model. Taking a region in southern China for example, the proposed shared freight station design was compared with the traditional freight station design. The results show that the single-hub H-S D-P network obtained by the traditional design could meet the demand when the D-P demand was relatively small; however, only the multi-hub H-S D-P network obtained by the shared freight station design could fulfil a large D-P demand in an efficient manner. The research findings show that the shared freight station is the future of D-P transport.

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Salient drag reduction of a heavy vehicle using modified cab-roof fairings

Cited by 43 publications

References 17 publications

An LES Investigation of the Near-Wake Flow Topology of a Simplified Heavy Vehicle

An LES Investigation of the Near-Wake Flow Topology of a Simplified Heavy Vehicle

Research on the Aerodynamic Characteristics of Tractor-Trailers with a Parametric Cab Design

Optimization of Drop-and-Pull Transport Network Based on Shared Freight Station and Hub-and-Spoke Network

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