Experimental Investigations of Vehicle Base Drag Reduction Using Passive Jet Boat-Tail Flow Control

Bartow, William; Moreyra, Andres; Hirst, Trevor; Woyczynski, Gregory; Lefebvre, Alexis; Zha, Gecheng

doi:10.4271/2014-01-2448

Cited by 7 publications

(4 citation statements)

References 9 publications

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“…When the width of the slots is increased, the speed of the flow through the slot increases, as shown by a lower static pressure on the slant surfaces ( Figure 22). This promotes the strengthening of the shear layers in the upper sides of the model, similar to that seen by Hirst and Bartow [19,20].…”

Section: Varney Et Al / Sae Int J Passeng Cars -Mech Syst / Volusupporting

confidence: 79%

“…Bartow and Hirst [19,20] carried out similar work on wing mirror geometries. Bartow et al [20] used an automotive mirror with a bell shaped internal geometry to duct the flow to the base of the mirror, this flow was vented circumferentially.…”

Section: Introductionmentioning

confidence: 99%

“…Bartow et al [20] used an automotive mirror with a bell shaped internal geometry to duct the flow to the base of the mirror, this flow was vented circumferentially. Whilst no experimental force measurements were presented for these geometries, particle image velocimetry (PIV) shows that increasing the intake area increases the mass flow rate and as a result reduces the size of the wake.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The Effect of Passive Base Ventilation on the Aerodynamic Drag of a Generic SUV Vehicle

Varney¹,

Passmore²,

Gaylard³

2017

SAE Int. J. Passeng. Cars - Mech. Syst.

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INTRODUCTIONAerodynamic drag is an increasing concern for vehicle manufacturers due to its impact on CO 2 emissions and fuel economy. For instance, the European Union will phase in significant penalties for CO 2 emissions above a mass-dependent limit curve from 2020 [1]. As Sport Utility Vehicles (SUVs) are the most popular body type [2], the methods of reducing their drag come under closer scrutiny, specifically when the success of these vehicles owes much to elements of design and utility.The blunt nature of SUV rear geometries arises from their historical use as working vehicles, with a need for maximal access to a large rear load space, whilst maintaining off-road capability. For squareback geometries, such as these, more than one-third of the aerodynamic drag is attributable to the rear surfaces [3], resulting from separation at the trailing edges leading to low pressure on the base.In order to combat the depressed static pressure on the base of vehicles a number of studies have been done to investigate base pressure recovery. Typical passive methods such as side tapering [4,5], roof tapering [4,6,7,8,9], roughness strips [10] and underbody tapering [11,12] have all been shown to result in base drag reductions.Active methods have also been tested with drag reductions being reported but little shown in terms of net energy reduction (as the systems require energy input); these include rolling trailing and leading edges [13], blowing [14] and thermal riblets [15].Both passive and active methods alter the shear layers bounding the wake of the vehicle and, as a result change the base pressure and reduce drag. Typically the reduction in drag is shown to be due to the increase in base pressure [4,5,7,8] Adrian Gaylard Jaguar Land Rover ABSTRACT Sports Utility Vehicles (SUVs) typically have a blunt rear end shape (for design and practicality), however this is not beneficial for aerodynamic drag. Drag can be reduced by a number of passive and active methods such as tapering and blowing into the base. In an effort to combine these effects and to reduce the drag of a visually square geometry slots have been introduced in the upper side and roof trailing edges of a squareback geometry, to take air from the freestream and passively injects it into the base of the vehicle to effectively create a tapered body.This investigation has been conducted in the Loughborough University's Large Wind Tunnel with the ¼ scale generic SUV model. The basic aerodynamic effect of a range of body tapers and straight slots have been assessed for 0° yaw. This includes force and pressure measurements for most configurations. The slots generate useful, but small, drag reductions with the best configurations giving reductions in drag coefficient (C d ) of approximately 0.01, whereas the best taper configurations reduce C d by close to 0.035. The slots also have a tendency to modify the lift.

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Section: Varney Et Al / Sae Int J Passeng Cars -Mech Syst / Volusupporting

confidence: 79%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The Effect of Passive Base Ventilation on the Aerodynamic Drag of a Generic SUV Vehicle

Varney¹,

Passmore²,

Gaylard³

2017

SAE Int. J. Passeng. Cars - Mech. Syst.

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“…A concept known as Jet Boat Tail(JBT) has been previously suggested and proven effective to reduce the drag of automobile rear view mirrors by Zha and his team [10,11,12,13,14]. This method is effective and convenient as it does not interfere with the base surface and does not create increase of the size of the body.…”

mentioning

confidence: 99%

Bluff Body Drag Reduction Using Passive Flow Control of Jet Boat Tail

Hirst

Yang

et al. 2015

SAE Int. J. Commer. Veh.

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Aerodynamic efficiency is at the forefront of concern when designing commercial road vehicles. As such, reducing aerodynamic drag has become the focal point of many research topics. Still, however, many commercial vehicles that are employed for the transportation of people and goods experience very high amounts of drag. Many of these high drag vehicles utilize configurations similar to rectangular prisms. Such vehicles include semi-trailer trucks, vans, buses, and SUV's. These vehicles are responsible for a substantial amount of miles traveled. Single-unit and combination trucks collectively consumed over 44 million gallons of gas in the US in 2010, accounting for over 26% of all gasoline consumed by motor vehicles that year[1]. A base surface is defined as a configuration ending with an abrupt cutoff by a flat or near flat surface [2]. The region immediately following the base surface is a volume that is of very low flow pressure and momentum, caused by this abrupt cut off. These characteristics make the base region a large source of drag, known as base drag. In fact, base drag is responsible for approximately 30% of all of the aerodynamic drag of a truck [2].

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Large eddy simulation of base drag reduction using jet boat tail passive flow control

et al. 2020

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Experimental Investigations of Vehicle Base Drag Reduction Using Passive Jet Boat-Tail Flow Control

Cited by 7 publications

References 9 publications

The Effect of Passive Base Ventilation on the Aerodynamic Drag of a Generic SUV Vehicle

The Effect of Passive Base Ventilation on the Aerodynamic Drag of a Generic SUV Vehicle

Bluff Body Drag Reduction Using Passive Flow Control of Jet Boat Tail

Large eddy simulation of base drag reduction using jet boat tail passive flow control

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