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Hosseini, Seyed M.
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Vinuesa, R., Hosseini, S. M., Hanifi, A., Henningson, D. S. & Schlatter, P. (2017). Pressure-gradient turbulent boundary layers developing around a wing section. Flow Turbulence and Combustion, 99(3-4), 613-641
Open this publication in new window or tab >>Pressure-gradient turbulent boundary layers developing around a wing section
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2017 (English)In: Flow Turbulence and Combustion, ISSN 1386-6184, E-ISSN 1573-1987, Vol. 99, no 3-4, p. 613-641Article in journal (Refereed) Published
Abstract [en]

A direct numerical simulation database of the flow around a NACA4412 wing section at R e (c) = 400,000 and 5(ay) angle of attack (Hosseini et al. Int. J. Heat Fluid Flow 61, 117-128, 2016), obtained with the spectral-element code Nek5000, is analyzed. The Clauser pressure-gradient parameter beta ranges from ae integral 0 and 85 on the suction side, and from 0 to - 0.25 on the pressure side of the wing. The maximum R e (oee integral) and R e (tau) values are around 2,800 and 373 on the suction side, respectively, whereas on the pressure side these values are 818 and 346. Comparisons between the suction side with zero-pressure-gradient turbulent boundary layer data show larger values of the shape factor and a lower skin friction, both connected with the fact that the adverse pressure gradient present on the suction side of the wing increases the wall-normal convection. The adverse-pressure-gradient boundary layer also exhibits a more prominent wake region, the development of an outer peak in the Reynolds-stress tensor components, and increased production and dissipation across the boundary layer. All these effects are connected with the fact that the large-scale motions of the flow become relatively more intense due to the adverse pressure gradient, as apparent from spanwise premultiplied power-spectral density maps. The emergence of an outer spectral peak is observed at beta values of around 4 for lambda (z) ae integral 0.65 delta (99), closer to the wall than the spectral outer peak observed in zero-pressure-gradient turbulent boundary layers at higher R e (oee integral) . The effect of the slight favorable pressure gradient present on the pressure side of the wing is opposite the one of the adverse pressure gradient, leading to less energetic outer-layer structures.

Place, publisher, year, edition, pages
Springer, 2017
Turbulent boundary layer, Pressure gradient, Wing section, Direct numerical simulation
National Category
Fluid Mechanics and Acoustics
urn:nbn:se:kth:diva-220718 (URN)10.1007/s10494-017-9840-z (DOI)000416838200005 ()2-s2.0-85027373953 (Scopus ID)
Swedish Research CouncilKnut and Alice Wallenberg FoundationSwedish e‐Science Research Center

QC 20180104

Available from: 2018-01-03 Created: 2018-01-03 Last updated: 2018-01-04Bibliographically approved

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