Aerodynamic Performance of a Drag Reduction Device on a Full-Scale Tractor/Trailer

Lanser, Wendy R.; Ross, James C.; Kaufman, Andrew E.

doi:10.4271/912125

Cited by 44 publications

(26 citation statements)

References 2 publications

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“…The presence of the flaps in the work of Grandemange act to remove the separated flow from the near wall region and leave a region of quiescent air next to the base. This is well known [3,4,5,10] to create an increase in the local base pressure, and is often presented as a passive method for drag reduction on commercial vehicles. In the work of Grandemange, changing the flap angles will then act to change the wake size and energy as well as the balance between the upper and lower vortex structures and the interaction between these.…”

Section: Top and Bottom Edge Tapermentioning

confidence: 99%

“…This can be achieved through passive optimization, for example geometry changes, vortex generators, flaps, and surface roughness, or using active control, for example, suction, blowing, oscillated suction and blowing, moveable vortex generators or flaps [2][3][4][5][6][7][8][9][10][11]. Active flow control is an attractive option because of the potential freedom it allows for vehicle styling as all that is required externally is the jet orifices.…”

Section: Introductionmentioning

confidence: 99%

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Influence of Short Rear End tapers on the Base Pressure of a Simplified Vehicle.

Perry

Passmore

Finney

2015

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

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Author, co-author (Do NOT enter this information. It will be pulled from participant tab in MyTechZone)Affiliation (Do NOT enter this information. It will be pulled from participant tab in MyTechZone) AbstractThis paper looks into the effect on base pressure of applying a high aspect ratio chamfer to all edges of a simplified squareback model (the Windsor model). The effects are investigated using force and moment measurements along with surface pressure measurements on the slanted surface and vertical base. The work forms part of a larger study to develop understanding of the mechanisms that influence overall base pressure and hence the resulting aerodynamic drag.A short slant (approx. 4% of model length) was applied to the trailing edges of the simplified vehicle model, representing the small rear end optimisation typical of many real vehicle geometries. Two experiments were performed: the first applied a chamfer at varying angles to the top and bottom edges; the second test looked at the same chamfer angle applied to the sides of the model geometry while the top and bottom angle remained square. The changes in drag are discussed and explained in the context of the base pressures and area weighted pressure coefficients.

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Section: Top and Bottom Edge Tapermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Influence of Short Rear End tapers on the Base Pressure of a Simplified Vehicle.

Perry

Passmore

Finney

2015

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

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“…One approach, we would term passive control, is to alter the geometry of the base region is some way. The boat-tail-plate attachment studied by Lanser et al, [8], and illustrated in Fig. 1, represents one possible alteration of base geometry.…”

Section: The Drag Coefficient Is Defined Asmentioning

confidence: 99%

“…1, represents one possible alteration of base geometry. Measurements on a full-scale tractor-trailer in the 80x120 Foot Wind Tunnel at NASA Ames indicate total drag reductions of the order of 10 percent, and good performance at angles of yaw (Lanser et al, [8]). Other more recent investigations of the boat-tail-plate attachment include Khalighi et al, [6], and Storms et al, [11].…”

Section: The Drag Coefficient Is Defined Asmentioning

confidence: 99%

Base Flaps and Oscillatory Perturbations to Decrease Base Drag

Hsu

Hammache

Browand

2004

The Aerodynamics of Heavy Vehicles: Trucks, Buses, and Trains

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The objective of this investigation is to study possible means for reducing the base drag of a tractor-trailer. The experiments are conducted in the Dryden wind tunnel at the USC Ground Vehicle Aerodynamics Laboratory. A roughly 1/15 scale model resembling a trailer is utilized for the study. The model is fitted with a shaped nose-piece to ensure attached flow over the forward portion of the model. The model is equipped with a force balance to measure drag. In addition base pressures are measured, and hot-wire wake surveys are conducted downstream from the model base. The Reynolds numbers (based on the square-root of the model cross-sectional area), range from 0.1 x 10 6 to 0.4 x 10 6 . Drag reduction is effected by means of flaps attached along the edges of the model base, and inclined inward to decrease the size of the downstream wake. In addition, an oscillatory perturbation is applied at the flap origin in an attempt to maintain attached flow for larger angles of flap inclination.The present study has found that a simple, passive base-flap deflection-no forcing whatsoever-produces significant drag saving. The maximum drag reduction is 0.06 -0.08 at an angle of 9-10 degrees. The magnitude of the saving is in accord with both early and recent measurements in other laboratories.The present results also show that oscillatory momentum addition has little effect on drag reduction unless the net oscillatory momentum flux coefficient is equal or greater than 0.1%. Increasing the oscillatory momentum perturbation to a coefficient value of 0.3% produces drag savings at angles greater than 9-10 degrees, but has very little effect upon the maximum saving at 9-10 degrees.To further study this anomalous behavior, follow-on experiments are planned to investigate a larger range of forcing amplitudes, and a variety forcing-function duty cycles. In addition, Digital Particle Image Velocimetry will be used to capture the detailed flow-field in the vicinity of the flap. 304T.-Y. Hsu, M. Hammache, and F. Browand

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“…Recommendation of the boattail vertical extension and the transition to the rear trailer skirt Lanser, et al (1991) and included rear trailer skirts in their wind tunnel study, but only Cooper explored the benefits of these skirts and their transition to the trailer boattail device and showed that they provided additional drag reduction. In our recent experiment, we observed improvements in drag reduction when the rear trailer skirts were installed and blended into the boattail.…”

mentioning

confidence: 99%

Aerodynamic Design Criteria for Class 8 Heavy Vehicles Trailer Base Devices to Attain Optimum Performance

Salari¹,

Ortega²

2010

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Aerodynamic Performance of a Drag Reduction Device on a Full-Scale Tractor/Trailer

Cited by 44 publications

References 2 publications

Influence of Short Rear End tapers on the Base Pressure of a Simplified Vehicle.

Influence of Short Rear End tapers on the Base Pressure of a Simplified Vehicle.

Base Flaps and Oscillatory Perturbations to Decrease Base Drag

Aerodynamic Design Criteria for Class 8 Heavy Vehicles Trailer Base Devices to Attain Optimum Performance

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