Decomposition of the mean friction drag in adverse-pressure-gradient turbulent boundary layers

Fan, YitongShanghai Jiao Tong Univ, Sch Aeronaut & Astronaut, Shanghai 200240, Peoples R China. (author)

QC 20201215
In this study, we exploit the Renard-Deck identity [J. Fluid Mech. 790, 339 (2016)] to decompose the mean friction drag in adverse-pressure-gradient turbulent boundary layers (APG-TBLs) into three components, associated with viscous dissipation, turbulence kinetic energy production, and spatial growth of the flow, respectively. We consider adverse-pressure-gradient turbulent boundary layers developing on flat plates and airfoils, with friction Reynolds numbers in the range 200 < Re-tau < 2000, and with Rotta-Clauser pressure-gradient parameters (beta) ranging from 0 to 50. The effects of Reynolds number, adverse pressure gradient, and the pressure-gradient history on the contributing components are individually investigated, and special attention is paid to the comparisons with zero-pressure-gradient turbulent boundary layers (ZPG-TBLs). Our results indicate that the inner peaks of the dissipation and production terms are located at y(+) approximate to 6 and y(+) approximate to 16.5, respectively, and their outer peaks scale with the 99% boundary-layer thickness (delta(99)), i.e., y/delta(99) approximate to 0.7 and 0.53, respectively. These results are independent of the friction Reynolds number, the magnitude of beta, and its development history. Moreover, the spatial-growth component is negative in the investigated APG-TBLs, and its magnitude increases with beta.

Li, WeipengShanghai Jiao Tong Univ, Sch Aeronaut & Astronaut, Shanghai 200240, Peoples R China. (author)
Atzori, Marco,1992-KTH,Strömningsmekanik och Teknisk Akustik,SimEx FLOW(Swepub:kth)u1zw21kp (author)
Pozuelo, RamonKTH,Teknisk mekanik,SimEx FLOW(Swepub:kth)u15es5iw (author)
Schlatter, PhilippKTH,Strömningsmekanik och Teknisk Akustik(Swepub:kth)u18wf7mg (author)
Vinuesa, RicardoKTH,Strömningsmekanik och Teknisk Akustik,SimEx FLOW(Swepub:kth)u12xffui (author)
Shanghai Jiao Tong Univ, Sch Aeronaut & Astronaut, Shanghai 200240, Peoples R China.Strömningsmekanik och Teknisk Akustik (creator_code:org_t)

By the author/editor: Fan, Yitong; Li, Weipeng; Atzori, Marco, 1 ...; Pozuelo, Ramon; Schlatter, Phili ...; Vinuesa, Ricardo

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