A Study of Reynolds Number Effects and Drag-Reduction Concepts on a Generic Tractor-Trailer

Storms, Bruce; Satran, D. R.; Heineck, James T.; Walker, Stephen

doi:10.2514/6.2004-2251

Cited by 43 publications

(25 citation statements)

References 3 publications

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“…The resulting drag curves for the three baseline configurations (DC/SF, DC/DF, LS/SF) with a 1.1 m tractor-trailer gap exhibit the behavior typical of that for heavy vehicles, wherein C A increases with increasing ψ (Fig. 7a), as seen in [5,8,9,12,13,14,15,33,34,37,38,39,40,60] and others. This increase in C A is due …”

Section: Resultsmentioning

confidence: 85%

“…Some of these second generation devices include boattails and trailer skirts, as well as tractor-trailer gap devices [2,3,7,9,12,13,14,15,22,23,31,32,35,38,42,44,45,54,55,59,60,61,62]. A number of studies, a sampling of which are shown in Tables 1-4, have either measured or estimated that these devices can produce fuel economy improvements when they are used both individually and in combination with one another.…”

Section: Introductionmentioning

confidence: 99%

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Aerodynamic drag reduction of class 8 heavy vehicles: a full-scale wind tunnel study

Ortega¹,

Salari²,

Brown³

et al. 2013

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Section: Resultsmentioning

confidence: 85%

Section: Introductionmentioning

confidence: 99%

Aerodynamic drag reduction of class 8 heavy vehicles: a full-scale wind tunnel study

Ortega¹,

Salari²,

Brown³

et al. 2013

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“…8), the drag curve of the 1:20-scale model was significantly higher and exhibited a larger increase with increasing yaw. This result is expected due to the significantly more complicated tractor geometry, the added trailer underbody detail, and the previously noted height mismatch between the tractor and trailer.…”

Section: A Baseline Configurationmentioning

confidence: 86%

“…A large subset of the configurations tested in the 7-by 10-Ft Tunnel were duplicated in the 12-Ft Pressure Tunnel to determine the effects of Reynolds number variation (Ref. 8).…”

Section: Introductionmentioning

confidence: 99%

DOE Project on Heavy Vehicle Aerodynamic Drag

McCallen¹,

Salari²,

Ortega³

et al. 2007

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ObjectiveClass 8 tractor-trailers consume 11-12% of the total US petroleum use. 1 At high way speeds, 65% of the energy expenditure for a Class 8 truck is in overcoming aerodynamic drag. The project objective is to improve fuel economy of Class 8 tractor-trailers by providing guidance on methods of reducing drag by at least 25%. A 25% reduction in drag would present a 12% improvement in fuel economy at highway speeds, equivalent to about 130 midsize tanker ships per year. Specific goals include:• Provide guidance to industry in the reduction of aerodynamic drag of heavy truck vehicles.• Develop innovative drag reducing concepts that are operationally and economically sound.• Establish a database of experimental, computational, and conceptual design information, and demonstrate the potential of new drag-reduction devices. Approach• Develop and demonstrate the ability to simulate and analyze aerodynamic flow around heavy truck vehicles using existing and advanced computational fluid dynamics (CFD) tools.• Through an extensive experimental effort, generate an experimental data base for code validation and for understanding of key drag producing flow characteristics • Provide industry with design guidance and insight into flow phenomena from experiments and computations.• Investigate aero devices (e.g., base flaps, tractor-trailer gap stabilizer, underbody skirts and wedges, blowing and acoustic devices), provide industry with conceptual designs of drag reducing devices, and demonstrate the full-scale fuel economy potential of these devices. Accomplishments• Organized and lead a very successful annual DOE Heavy Vehicle Working Group Meeting with active industry participation. The objective of these annual meetings is to provide a forum for reviewing industry needs, presenting new drag reduction concepts, discussing project direction, and identifying areas of collaboration between industry and DOE supported R&D participants from National Labs, universities and other research organizations. • New flow conditioning concept of "bleeding-flow" device has been shown computationally to provide significant gap flow and trailer base drag reduction. Plans are to perform reduced-scale tests at NASA and full-scale tests at NRC • Providing a consistent, realistic, comprehensive assessment of the energy balance when evaluating devices like with the "bleeding flow" device is needed. Consider and report: o energy used by active features o weight of all components o Impact of design on fleet operation in terms of dollars saved per ton hauled in addition to changes in drag coefficient or fuel use rate. o Yaw-averaged drag values when evaluating design changes.• Tractor and trailer underbody experiments at NASA show small improvement in tractor drag with the use of tractor belly pans or with the covering of cross ribs under the trailer. Experiments also showed that trailer side skirts are still the most promising drag reduction approach.• Evaluation of the impact of small changes in radiator or grille dimensions has revealed that the ...

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“…In 1978 Hucho [50] raised the initial concern, in 1981 Gilhaus [ [84] executed a sub-scale model study in a NASA pressure wind tunnel that was able to obtain full scale Reynolds number data on a 0.125 scale model. Storms test data clearly suggest that the minimum width-based Reynolds number is greater than 1 million and may be as large as 3 million.…”

Section: Introductionmentioning

confidence: 99%

A Review of Reynolds Number Effects on the Aerodynamics of Commercial Ground Vehicles

Wood¹

2012

SAE Int. J. Commer. Veh.

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A review of Reynolds number scaling and high Reynolds number simulation for commercial ground vehicles is presented. The supporting data was extracted from published wind tunnel tests, coastdown tests and computational studies for complete vehicles and vehicle components. For complex vehicles the data suggest that the use of forced transition for higher Reynolds number simulation is a viable test technique however various component specific schemes may be required to replicate the aerodynamics of a full-scale vehicle. The Reynolds number sensitivity of; boundary layer transition control, surface curvature effects, bluff base flows, wheel/tire aerodynamics, and complete vehicle aerodynamics is presented. The data show that the width-based transcritical Reynolds number for commercial vehicles is between 1 and 3 million with the averaged values for edge radius, wheels and full vehicle data sets between 1.6 and 1.8 million. A minimum width-based transcritical Reynolds number value of 3 million is recommended for simulating the aerodynamics of full-scale commercial vehicles operating at a width-based Reynolds number greater than 3 million. If the dominant aerodynamic and fluid dynamic features of the vehicle are well established the minimum width-based transcritical Reynolds number value that may be used is 2 million. To ensure an accurate simulation of full-scale vehicles operating below the 3 million transcritical value future studies should be performed at the vehicle full-scale Reynolds number.

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A Study of Reynolds Number Effects and Drag-Reduction Concepts on a Generic Tractor-Trailer

Cited by 43 publications

References 3 publications

Aerodynamic drag reduction of class 8 heavy vehicles: a full-scale wind tunnel study

Aerodynamic drag reduction of class 8 heavy vehicles: a full-scale wind tunnel study

DOE Project on Heavy Vehicle Aerodynamic Drag

A Review of Reynolds Number Effects on the Aerodynamics of Commercial Ground Vehicles

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