Title
PIV Measurements on the Change of the Three-Dimensional Wake Structures by an Air Spoiler of a Road Vehicle
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 several x-y, y-z and z-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 the λ$_2$-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.
Year
DOI
Venue
2008
10.1007/BF03181913
J. Visualization
Keywords
Field
DocType
particle image velocimetry (PIV),road vehicle,air spoiler,three-dimensional wake,vortex line,λ,2,method
Wake,Wingtip vortices,Particle image velocimetry,Velocity gradient,Vertical direction,Flow (psychology),Vortex,Aerospace engineering,Optics,Mechanics,Downwash,Physics
Journal
Volume
Issue
ISSN
11
1
1343-8875
Citations 
PageRank 
References 
4
0.90
3
Authors
3
Name
Order
Citations
PageRank
Junghyun Kim1329.07
J. Sung251.84
S. Kim3516.55