Flow physics in the turbulent near wake of a flat plate

The symmetric near wake of a flat plate with a circular trailing edge, exhibiting pronounced shedding of wake vortices, is investigated via a direct numerical simulation. The separating plate boundary layers are turbulent and statistically identical. The present study focuses on the vortical structu...

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Veröffentlicht in:Journal of fluid mechanics 2013-06, Vol.724, p.704-733
1. Verfasser: Rai, Man Mohan
Format: Artikel
Sprache:eng
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Zusammenfassung:The symmetric near wake of a flat plate with a circular trailing edge, exhibiting pronounced shedding of wake vortices, is investigated via a direct numerical simulation. The separating plate boundary layers are turbulent and statistically identical. The present study focuses on the vortical structures, the distribution of phase-averaged velocity statistics and vorticity fluctuations in the near wake. Braid and vortex core regions are investigated via contours of instantaneous vorticity and pressure with an emphasis on the three-dimensionality of near-wake structures. Rib vortices are observed in the braids. The vortex cores are populated with both ribs that wrap themselves around the cores and spanwise-elongated regions of spanwise vorticity near the centres of the cores. Production terms in the transport equations for phase-averaged fluctuating vorticity show that stretching of rib vortices via the phase-averaged strain rate produces significantly less turbulent vorticity than turbulent stretching in the braids and cores.
ISSN:0022-1120
1469-7645
DOI:10.1017/jfm.2013.185