Please use this identifier to cite or link to this item: https://doi.org/10.1080/14685240600595735
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dc.titleDNS of low Reynolds number turbulent flows in dimpled channels
dc.contributor.authorWang, Z.
dc.contributor.authorYeo, K.S.
dc.contributor.authorKhoo, B.C.
dc.date.accessioned2014-06-17T06:17:50Z
dc.date.available2014-06-17T06:17:50Z
dc.date.issued2006
dc.identifier.citationWang, Z., Yeo, K.S., Khoo, B.C. (2006). DNS of low Reynolds number turbulent flows in dimpled channels. Journal of Turbulence 7 : 1-31. ScholarBank@NUS Repository. https://doi.org/10.1080/14685240600595735
dc.identifier.issn14685248
dc.identifier.urihttp://scholarbank.nus.edu.sg/handle/10635/59981
dc.description.abstractDirect numerical simulation (DNS) is performed to study turbulent flows over dimpled surfaces in a channel. Results on mean field and second-order quantities are obtained. 'Horseshoe' vortices can be observed in the dimples of sparse arrays. As inter-dimple separation is reduced, the 'feet' of the horseshoe vortices are gradually lifted off the dimple surface, and the resulting flow structures in the cavities become flattened and stretched to become something akin to two-dimensional separation bubbles. At the higher dimple density, the stream traces near the surface also develop a distinct formation similar to what had been observed in earlier Reynolds-averaged Navier-Stokes (RANS) simulations (Isaev, S.A., Leont'ev, A.I. and Baranov, P.A., 2000, Technical Physics Letters, 26, 15; Lin, Y.L., Shih, T.I.-P. and Chyu, M.K., 1999, ASME paper, 99-GT-263; Lin, Y.L. Shih, T.I.-P., 2001, International Journal of Transfer Phenomena, 3, 1). Regions of high turbulence intensity are found above the downstream half of the dimples and along their side edges. These regions coincide with the locations of vortex shedding found in the experiments of Ligrani et al. (2001, Physics of Fluids, 13, 3442) and the locations of vorticity concentrations observed in Park et al. (2004, Numerical Heat Transfer, Part A (Applications), 45(1), 1) and Won and Ligrani (2004, Numerical Heat Transfer, Part A (Applications), 46(6), 549). For a fixed mean pressure gradient, it is observed that the flow rates through the channels are reduced by the presence of dimples. This indicates that the dimpled channels we have studied so far have larger drag than flat-wall channels. Computed friction coefficients for dimpled channels also confirmed the conclusion. © 2006 Taylor & Francis.
dc.description.urihttp://libproxy1.nus.edu.sg/login?url=http://dx.doi.org/10.1080/14685240600595735
dc.sourceScopus
dc.subjectDimple
dc.subjectDNS
dc.subjectHeat transfer
dc.subjectMixing enhancement
dc.subjectRough wall
dc.subjectTurbulent flow
dc.typeArticle
dc.contributor.departmentMECHANICAL ENGINEERING
dc.contributor.departmentTEMASEK LABORATORIES
dc.description.doi10.1080/14685240600595735
dc.description.sourcetitleJournal of Turbulence
dc.description.volume7
dc.description.page1-31
dc.identifier.isiut000238152700001
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