Near-asymptotics overlap solutions for transport moments in turbulent channesl and boundary layers
ORAL
Abstract
The log profile overlap solutions for turbulent channel have been complemented recently by solutions for the dissipation$^{1}$, $\varepsilon$ and the kinetic energy$^2$, $\langle q^2 \rangle/2$. The dissipation varies as $1/y^+$, while the turbulence kinetic energy varies logarithmically. The Reynolds shear stress is nearly constant. We show from similar arguments that the transport moments, $T =-\langle p v \rangle/\rho - \langle q^2 v \rangle/2 +2 \nu \langle u_i s_{ij} \rangle$, also vary logarithmically. So all the terms in the kinetic energy balance in overlap region, $[\partial T/\partial y - \langle uv \rangle dU/dy - \varepsilon]=0$, vary inversely with $y^+$. Boundary layer results are the power-law equivalents, but indistinguishable. Both are shown to be consistent with recent experimental and DNS data. This presents a problem for the usual eddy viscocity models for this region, $\nu_t \propto \langle q^2 \rangle^2 / \varepsilon$, since both cannot be true. References: 1) Wosnik, M. {\it etal} (2000) JFM 421, 115; 2) Hultmark, M. (2012) JFM 707,575
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Authors
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William K. George
Dept. of Aeronautics, Imperial College of London, London, UK, Imperial College London
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Jean-Marc Foucaut
Univ. Lille, Onera, CNRS, Centrale Lille, Arts et Métiers Paris Tech, FRE 2017 - LMFL - Laboratoire de Mécanique des Fluides de Lille Kampé de Fériet,
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Jean-Philippe Laval
Univ. Lille, Onera, CNRS, Centrale Lille, Arts et Métiers Paris Tech, FRE 2017 - LMFL - Laboratoire de Mécanique des Fluides de Lille Kampé de Fériet,