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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 | 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 |