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Wind-Tunnel Modelling off Commercial Vehicle Drag-Reducing Devices: Three Case Studies
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Abstract
Road and wind-tunnel tests are presented which examine the drag coefficient reductions from aerodynamic devices fitted to three trucks.
A modified SAE Type II procedure utilising an instrumented chase car, evaluated on-road, constant-speed drag reductions as a function of yaw angle. At 100 km/h, turbulence intensities of 1% - 4% were measured.
The wind-tunnel results generally overestimated drag savings, particularly at high yaw angles. This was greater for cabin deflectors than for solid fairings. Simulating higher turbulence intensities gave improved agreement and it is argued that turbulence is a dominant modelling parameter.
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Authors
Citation
Watkins, S., Saunders, J., and Hoffman, P., "Wind-Tunnel Modelling off Commercial Vehicle Drag-Reducing Devices: Three Case Studies," SAE Technical Paper 870717, 1987, https://doi.org/10.4271/870717.Also In
References
- Walston W.H. Jr. Buckley F.T. Jr. Marks C.H. “Test Procedures for the Evaluation of Aerodynamic Drag on full-scan vehicles in Windy Environments” SAE 760106
- Buckley F.T. Jr. Marks C.H. Walston W.H. Jr. “A Study of Aerodynamics Methods of improving Truck Fuel Economy” Univ. of Maryland 1978
- Saunders J.W. Watkins S. Hoffmann P.H. Buckley F.T. Jr. “Comparison of On-Road and Wind-Tunnel Tests for Tractor-Trailer Aerodynamic Devices and Fuel Savings Predictions” SAE 850286 1985
- Buckley F.T. Jr. “An Improved Over-The-Road Test Method for Determining the Fuel Savings Benefit of a Truck Aerodynamic Drag Reducing Device” SAE 850285 1985
- SAE “Joint TMS/SAE fuel consumption test procedure-Type 11” SAE 01321 1981
- Watkins S, “Commercial Vehicles Aerodynamics - wind Tunnel and Road Comparison” M. Eng. Thesis Royal Melbourne institute of Technology Australia 1986
- Watkins S. Hoffmann P.H. Saunders J.W. “Comparison of On-Road and Wind-Tunnel Tests for Rigid Truck Aerodynamic Devices” 9th Australasian Fluid Mechanics Conference Auckland, New Zealand 1986
- SAE “SAE Wind Tunnel Test Procedure for Trucks and Buses” SAE J1252 1979
- Cooper K.R. “The Wind-Tunnel Simulation of Surface Vehicles” J. Wind Eng. Ind. Aero 17 167 198 1984
- Bearmen P.W., “Bluff Body Flows Applicable to Vehicle Aerodynamics” Presented at the A.S.M.E. Meeting an Aerodynamics and Transportation 1979
- Paul J.C. LaFond J.G. “Analysis and Design of Automobile Forebodies Using Potential Flow Theory and a Boundary Layer Separation Criterion” SAE 830999
- Stratford B.S. “The Prediction of Separation of the Turbulent Boundary Layer” J. Fluid Mech. 5 1959
- Cooper K.R. “The Effect of Front-Edge Rounding and Rear-Edge Shaping on the Aerodynamic Drag of Bluff Vehicles in Ground Proximity” SAE 850288
- Blackmore M. “The Effect of Ground Simulation on a Slab Sided Truck” M. Eng. Thesis Dept. of Mech. Eng., University of Melbourne Australia 1984
- Gilhaus A. Private Communication 1981
- Cooper K.R. Private Communication 1981
- Cooper K.R. Campbell W.F. “An Examination of the Effects of Wind Turbulence on the Aerodynamic Drag of Vehicles” J. Wind Enq. and ind. Aero. 9 1981
- Lawson T.V. “Wind Effects on Buildings” 1 and 2 Applied Science Publishers Ltd. 1980
- Cooper R.K. “Atmospheric Turbulence with respect to Ground Vehicles” J. Wind. Eng. Ind. Aero. 17 1984
- Balzer L.A. “Atmospheric Turbulence Encountered by High-Speed Ground Transport Vehicles” J. Mech. Eng. Sci. 19 1977
- Thompson R.S. “Experimental and Theoretical Study of the Wake of a Block-Shaped Vehicle in a Shear Free Boundary Flow” Atmospheric Environment 16 12 1982
- Flay R.G.J. “Structure of a Rural Atmospheric Boundary Layer Near the Ground” Phd. Thesis Univ. Canterbury Christchurch, New Zealand 1978
- Smith N.P. “Wind Gusts Measured on High-Speed Roads” Motor industry Research Association (U.K.) Report No. 1972/7