Revisiting History Effects in Adverse-Pressure-Gradient Turbulent Boundary Layers

Autor: Andrea Ianiro, Stefano Discetti, Ramis Örlü, Philipp Schlatter, Ricardo Vinuesa, Carlos Sanmiguel Vila
Přispěvatelé: European Commission
Jazyk: angličtina
Rok vydání: 2017
Předmět:
Zdroj: Flow, Turbulence and Combustion
e-Archivo. Repositorio Institucional de la Universidad Carlos III de Madrid
instname
e-Archivo: Repositorio Institucional de la Universidad Carlos III de Madrid
Universidad Carlos III de Madrid (UC3M)
ISSN: 1573-1987
1386-6184
Popis: The goal of this study is to present a first step towards establishing criteria aimed at assessing whether a particular adverse-pressure-gradient (APG) turbulent boundary layer (TBL) can be considered well-behaved, i.e., whether it is independent of the inflow conditions and is exempt of numerical or experimental artifacts. To this end, we analyzed several high-quality datasets, including in-house numerical databases of APG TBLs developing over flat-plates and the suction side of a wing section, and five studies available in the literature. Due to the impact of the flow history on the particular state of the boundary layer, we developed three criteria of convergence to well-behaved conditions, to be used depending on the particular case under study. (i) In the first criterion, we develop empirical correlations defining the R e (oee integral) -evolution of the skin-friction coefficient and the shape factor in APG TBLs with constant values of the Clauser pressure-gradient parameter beta = 1 and 2 (note that beta = delta (au)/tau (w) dP (e) /dx, where delta (au) is the displacement thickness, tau (w) the wall-shear stress and dP (e) /dx the streamwise pressure gradient). (ii) In the second one, we propose a predictive method to obtain the skin-friction curve corresponding to an APG TBL subjected to any streamwise evolution of beta, based only on data from zero-pressure-gradient TBLs. (iii) The third method relies on the diagnostic-plot concept modified with the shape factor, which scales APG TBLs subjected to a wide range of pressure-gradient conditions. These three criteria allow to ensure the correct flow development of a particular TBL, and thus to separate history and pressure-gradient effects in the analysis. RV, RO and PS acknowledge the funding provided by the Swedish Research Coun-cil (VR) and from the Knut and Alice Wallenberg Foundation. RO acknowledges the financial support of the Lundeqvist foundation. CSV acknowledges the financial support from Universidad Carlos III de Madrid within the program “Ayudas para la Movilidad del Programa Propio de Investigación”. CSV, SD and AI were partially supported by the COTURB project (Coherent Structures in Wall-bounded Turbulence), funded by the European Research Council Coturb Grant No. ERC-2014.AdG-669505. The simulations were per-formed on resources provided by the Swedish National Infrastructure for Computing (SNIC) at PDC (KTH Stockholm).
Databáze: OpenAIRE
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