Effect of Test Section Configuration on Aerodynamic Drag Measurements

Hoffman, Jeffrey; Martindale, Bill; Arnette, Stephen A.; Williams, Jack E.; Wallis, Stan

doi:10.4271/2001-01-0631

Cited by 29 publications

(7 citation statements)

References 8 publications

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Section: Description Of the Bus Modelmentioning

confidence: 99%

“…This model is chosen because of its simple appearance with typical characters of a common bus, and it has been widely investigated in the aerodynamic fields [10][11][12]. The model dimensions shown in Table 1 come from Hoffman et al [10]. The wake flow structure of this bus is shown in Figure 2; the flows from the upper surface and side surfaces meet in this region and form a pair of counterrotating trailing vortices.…”

Section: Description Of the Bus Modelmentioning

confidence: 99%

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A New Method to Optimize the Wake Flow of a Vehicle: The Leading Edge Rotating Cylinder

Shao

Yao

Zhang

et al. 2017

Mathematical Problems in Engineering

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The wake flow of a vehicle significantly influences its aerodynamic performance and the stability during high-speed drive. Therefore, optimization of the vehicle wake flow is an effective way to improve its aerodynamic performance and further improve the handling stability and fuel economy. In this paper, a new method, the leading edge rotating cylinder, is used to optimize the wake flow of a vehicle. According to the results of simulations, this method can reduce the pressure drag, increase the negative lift force, and strengthen the stability of the vehicle under crosswind. Furthermore, this method optimizes not only the wake flow of the vehicle with rotating cylinders but also the interactive vehicles in the driving route in overtaking maneuvers or platoon driving. In conclusion, this method effectively optimizes the flow fields around the vehicles, and it significantly helps to improve the handling stability and fuel economy of the vehicle.

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Section: Description Of the Bus Modelmentioning

confidence: 99%

Section: Description Of the Bus Modelmentioning

confidence: 99%

A New Method to Optimize the Wake Flow of a Vehicle: The Leading Edge Rotating Cylinder

Shao

Yao

Zhang

et al. 2017

Mathematical Problems in Engineering

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“…Wickern [7] had his first summary on the application of automotive wind tunnel corrections, followed by Wickern and Schwartekopp [8], who investigated the nozzle gradient effects in open jet wind tunnels. Hoffman et al [9,10] studied the test section configuration effects on the aerodynamic drag and lift predictions as well, with different vehicle shapes using the Ford/Sverdrop Drivability Test Facility. Based on experiments carried out using various vehicle models, Mercker and his co-workers were able to quantify the effects of the static pressure gradients in wind tunnels [11].…”

Section: Introductionmentioning

confidence: 99%

Computational Analyses of the Effects of Wind Tunnel Ground Simulation and Blockage Ratio on the Aerodynamic Prediction of Flow over a Passenger Vehicle

2020

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With the fast-paced growth of computational horsepower and its affordability, computational fluid dynamics (CFD) has been rapidly evolving as a popular and effective tool for aerodynamic design and analysis in the automotive industry. In the real world, a road vehicle is subject to varying wind and operating conditions that affect its aerodynamic characteristics, and are difficult to reproduce in a traditional wind tunnel. CFD has the potential of becoming a cost-effective way of achieving this, through the application of different boundary conditions. Additionally, one can view wind tunnel testing, be it a fixed-floor or rolling road tunnel, as a physical simulation of actual on-road driving. The use of on-road track testing, and static-floor, and rolling-road wind tunnel measurements are common practices in industry. Subsequently, we investigated the influences of these test conditions and the related boundary conditions on the predictions of the aerodynamic characteristics of the flow field around a vehicle using CFD. A detailed full-scale model of Hyundai Veloster with two vehicle configurations, one with the original and the other with an improved spoiler, were tested using a commercial CFD code STAR-CCM+ from Siemens. Both vehicle configurations were simulated using four different test conditions, providing overall eight different sets of simulation settings. The CFD methodology was validated with experimental data from the Hyundai Aero-acoustic Wind Tunnel (HAWT), by accurately reproducing the test section with static floor boundary conditions. In order to investigate the effect of the blockage ratio on the aerodynamic predictions, the vehicle models were then tested with moving ground plus rotating wheel boundary conditions, using a total of four virtual wind tunnel configurations, with tunnel solid blockage ratios ranging from 1.25%, which corresponds to the actual HAWT, to 0.04%, which presents an open air driving condition.

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“…In aerodynamics the most critical criteria is Reynolds number which guides vehicle design principles and governs the use of testing and analysis tools. A review of the literature [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,…”

Section: Introductionmentioning

confidence: 99%

“…The information presented in this paper has been extracted from published works and where available accepted correlation parameters and summary data plots are presented. The evaluation of complete vehicles made use of references 6,8,9,11,13,15,16,18,20,21,22,23,24,26,27,29,33,36,37,44,45,48,49,50,51,52,56,64,70,73,74,77,80,81,82,83,84,85,86,87,91,93,94,95,96,97,100 …”

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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Effect of Test Section Configuration on Aerodynamic Drag Measurements

Cited by 29 publications

References 8 publications

A New Method to Optimize the Wake Flow of a Vehicle: The Leading Edge Rotating Cylinder

A New Method to Optimize the Wake Flow of a Vehicle: The Leading Edge Rotating Cylinder

Computational Analyses of the Effects of Wind Tunnel Ground Simulation and Blockage Ratio on the Aerodynamic Prediction of Flow over a Passenger Vehicle

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

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