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PIV measurements on the change of the three-dimensional wake structures by an air spoiler of a road vehicle

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Abstract

The three-dimensional vortical structures formed in the wake behind a road vehicle were measured using a particle image velocimetry (PIV) technique and the change of the structures by the existence of an air spoiler was investigated. The measurements were carried out in severalx-y, y-z andz-x planes to obtain full three-dimensional flow fields, including an out-of-plane velocity component, obtained by interpolating the velocities in the other plane. Then, the velocity gradient tensor is evaluated to obtain the vortex core by theλ 2-definition. The relationship between streamwise, longitudinal and spanwise vortices is systematically analyzed by overlapping the vortex lines and vortex cores and the whole flow topology is compared in both cases with and without an air spoiler. As a result, an air spoiler was found to weaken the C-pillar vortices producing strong wing tip vortices, which reduce downwash flow and longitudinal vortices increase in the vertical direction. The recirculation zone formed when an air spoiler is installed is higher and narrower than without a spoiler.

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Jin Seok Kim: He obtained his master degree of engineering in mechanical engineering from Sunchon National University, Korea in 2005 and is currently a Ph.D. candidate in the same university.

Jaeyong Sung: He received his master and Ph.D. degrees in mechanical engineering in 1996 and 2001, respectively from Seoul National University, Korea, and worked for Digital Appliance Laboratory of LG Electronics Inc. as a senior researcher. Also he taught in mechanical and automotive engineering of Sunchon National University as a professor. And he has been working in department of mechanical engineering in Seoul National University of Technology as a professor since 2004. His research interests are all the areas related to PIV technology, hemodynamics, biochips, rarefied gas flow with DSMC, etc.

Sungcho Kim: He received his master and Ph.D. degrees in aeronautical engineering in 1985 and 1989, respectively from KAIST, Korea, and worked in Central Technology Institute of Daewoo Heavy Industry Ltd. He researched in Mississippi State University and University of California, Santa Barbara as a visiting scholar in 1994 and 2000, respectively. And he served as the dean in college of engineering, Sunchon National University, and has been working in school of mechanical and aerospace engineering in Sunchon National University as a professor since 1989. His research area is experimental and computational fluid engineering.

Jeong Soo Kim: He received his master and Ph.D. degrees in aeronautical engineering in 1987 and 1992, respectively from KAIST, Korea, and worked for KIMM, ADD, and KARI as a principal researcher. Also he researched in TRW(USA) as an assistant program manager from 1996 to 1998. And he has been a faculty member in school of mechanical and aerospace engineering in Sunchon National University since 2004. His research interests are satellite propulsion system, measurement and visualization of injector spray pattern using PDA, combustion, test and evaluation of liquid rocket engine, etc.

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Kim, J.S., Sung, J., Kim, S. et al. PIV measurements on the change of the three-dimensional wake structures by an air spoiler of a road vehicle. J Vis 11, 45–54 (2008). https://doi.org/10.1007/BF03181913

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  • DOI: https://doi.org/10.1007/BF03181913

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