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Wake Structures of Rectangular Bodies with Radiused Edges Near a Plane Surface
ISSN: 0148-7191, e-ISSN: 2688-3627
Published March 01, 1999 by SAE International in United States
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Almost all published results of wake measurements for ground vehicles or similar shapes have included very limited information on streamwise development of wake structures. This is typically a result of the fact that the wake measurements have been conducted as parts of particular vehicle development efforts. So the focus has been on the incremental changes in the wakes associated with alternative geometries or buildup of various parts. The objectives are typically reached by limiting the surveys to a single streamwise plane. The present study, by contrast, is a study of wake development for a series of relatively simple rectangular shapes with radiused edges with a systematic variation in the ratio of height to width or “Aspect Ratio”. Measurements include surveys in several streamwise planes and surveys in several longitudinal planes selected to produce volumetric data sets that give good description of the development of the wakes to about 2 hydraulic diameters downstream of the base. The baseline shapes are smooth on all surfaces. In addition to the effect of aspect ratio, a systematic variation of roughness on the lower surface is included. The present study was motivated by recent tests for a commercial van with various roof heights in which force measurements suggested that drag coefficient for taller (higher aspect ratio) vehicles is lower than drag coefficient for shorter (lower aspect ratio) vehicles. This is the opposite of the trend expected from data on basic shapes in the literature. The primary force data and comparisons to other vehicles are given in another paper. This paper provides an extensive data set on wakes for a basic series of shapes and for selected variations in lower surface roughness which is intended to encompass typical values representative of current vehicles.
CitationBarlow, J., Guterres, R., Ranzenbach, R., and Williams, J., "Wake Structures of Rectangular Bodies with Radiused Edges Near a Plane Surface," SAE Technical Paper 1999-01-0648, 1999, https://doi.org/10.4271/1999-01-0648.
- Bearman, P. W., Developments in the Understanding of Bluff Body Flows JSME International Journal, Series B 41 1 998 103 114
- Cogotti, A., A Strategy for Optimum Surveys of Passenger-Car Flow Fields SAE Paper 890374 , Society of Automotive Engineers Warrendale, Pa. 1989
- Onorato, M., Costelli, A. F., Garrone, A., Drag Measurements Through Wake Analysis SAE Paper 840302 , Society of Automotive Engineers Warrendale, Pa. 1984
- Hackett, J. E., Williams, J. E., Patrick, J., Jr., Wake Traverses Behind Production Cars and their Interpretation SAE Paper 850280 , Society of Automotive Engineers Warrendale, Pa. 1985
- Ahmed, S. R., Ramm, G., Faltin, G., Some Salient Features of the Time Averaged Ground Vehicle Wake SAE Paper 840300 , Society of Automotive Engineers Warrendale, Pa. 1984
- Nakagushi, H., Recent Japanese Research on Three-Dimensional Bluff Body Flows Relevant to Road Vehicle Aerodynamics University of Tokyo Japan 1978
- Maull, D. J., Mechanisms of Two and Three-Dimensional Base Drag Cambridge University 1978
- Bearman, P. W., Near Wake Flows Behind Two and Three-Dimensional Bluff Bodies Journal of Wind Engineering and Industrial Aerodynamics 69-71 1997 33 54
- Tieleman, H. W., Editor, Progress in Bluff Body Aerodynamics, proceedings of the 3rd International Colloquium on Bluff Body Aerodynamics and Applications Blacksburg, VA 1996
- Hoerner, S. F., Fluid Dynamic Drag Hoerner Fluid Dynamics Vancouver, WA 1965
- Gallington, R. W., Measurement of Very Large Flow Angles with Non-Nulling Seven-Hole Probes Aeronautics Digest-Spring/Summer 1980, USAFA-TR-80-17 USAF Academy 1980
- Gupta, M., Comparison of Seven Hole and Spherical Pressure Probes Master of Science Thesis Department of Aerospace Engineering University of Maryland 1986
- Everett, K. N., Gerner, A. A., Durston, D. A., Seven-Hole Cone Probes for High Angle Flow Measurement: Theory and Calibration AIAA Journal 21 7 1983 992 998
- Maskell, E. C., A Theory of the Blockage Effects on Bluff Bodies and Stalled Wings in a Closed Wind Tunnel ARC R&M 3400 1965