dc.contributor.author |
Wang, X.W.
|
|
dc.contributor.author |
Zhou, Y.
|
|
dc.contributor.author |
Pin, Y.F.
|
|
dc.contributor.author |
Chan, T.L.
|
|
dc.date.accessioned |
2014-12-09T12:43:34Z |
|
dc.date.available |
2014-12-09T12:43:34Z |
|
dc.date.issued |
2012 |
|
dc.description.abstract |
Paper presented at the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012. |
en_ZA |
dc.description.abstract |
The lasting high fuel cost has recently inspired resurgence in drag reduction research for vehicles, which calls for a thorough understanding of the vehicle wake. The simplified Ahmed vehicle model is characterized by controllable flow separation, thus especially suitable for this purpose. In spite of a considerable number of previous investigations, our knowledge of flow around this model remains incomplete. This work aims to revisit turbulent flow structure behind this model. Two rear slant angles, i.e., α = 25º and 35º, of the model were examined, representing two distinct flow regimes. The Reynolds number was 5.26×104 based on the model height (H) and incident flow velocity. Using particle image velocimetry (PIV), flow was measured with and without a gap (g/H = 0.174) between the vehicle underside and ground in three orthogonal planes, viz. the x-z, x-y and y-z planes, where x, y and z are the coordinates along longitudinal, transverse and spanwise directions, respectively. The flow at g/H = 0 serves as an important reference for the understanding of the highly complicated vehicle wake (g/H ≠ 0). While reconfirming the well documented major characteristics of the mean flow structure, both instantaneous and time-averaged PIV data unveil a number of important features of the flow structure, which have not been previously reported. As such, considerably modified flow structure models are proposed for both regimes. The time-averaged velocities, second moments of fluctuating velocities and vorticity components are presented and discussed, along with their dependence on g/H in the two distinct flow regimes. |
en_ZA |
dc.description.librarian |
dc2014 |
en_ZA |
dc.format.extent |
10 pages |
en_ZA |
dc.format.medium |
PDF |
en_ZA |
dc.identifier.citation |
Wang, XW, Zhou, Y, Pin, YF & Chan, T 2012, Three-dimensional flow structure behind an Ahmed vehicle model, Paper presented to the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012. |
en_ZA |
dc.identifier.isbn |
9781868549863 |
|
dc.identifier.uri |
http://hdl.handle.net/2263/42891 |
|
dc.language.iso |
en |
en_ZA |
dc.publisher |
International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics |
en_ZA |
dc.relation.ispartof |
HEFAT 2012 |
en_US |
dc.rights |
University of Pretoria |
en_ZA |
dc.subject |
Drag reduction research |
en_ZA |
dc.subject |
Drag reduction for vehicles |
en_ZA |
dc.subject |
Vehicle wake |
en_ZA |
dc.subject |
Ahmed vehicle model |
en_ZA |
dc.subject |
Turbulent flow structure |
en_ZA |
dc.subject |
Particle image velocimetry |
en_ZA |
dc.subject |
PIV |
en_ZA |
dc.subject |
Flow structure |
en_ZA |
dc.title |
Three-dimensional flow structure behind an Ahmed vehicle model |
en_ZA |
dc.type |
Presentation |
en_ZA |