Consistently formulated eddy-viscosity coefficient for k-equation model

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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
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Date

2019-01-01

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Department of Energy and Mechanical Engineering

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Language

en

Pages

36

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Journal of Turbulence, Volume 19, issue 11-12, pp. 959-994

Abstract

An approach to devising a consistency formulation for Pk/ϵ(production-to-dissipation ratio) is proposed to obtain a non-singular Cμ(coefficient of eddy-viscosity) embedded in the one-equation model based on the turbulent kinetic energy k. The dissipation rate ε is evaluated with an algebraically prescribed length scale having only one adjustable coefficient, accompanied by an anisotropic function qϵ enhancing the dissipation in non-equilibrium flow regions. The model accounts for the distinct effects of low Reynolds number (LRN) and wall proximity. The stress-intensity ratio Rb = u1u2/k is formulated as a function of local variables without resorting to a constant √C* μ= 0.3. The parameters Rb and Pk/ϵ entering the turbulence production Pk prevents presumably the overestimation of Pk in flow regions where non-equilibrium effects could result in a misalignment between turbulent stress and mean strain rate with a linear eddy-viscosity model. A comparative assessment of the present model with the Spalart–Allmaras (SA) one-equation model and the shear stress transport (SST) k–ω model is provided for well-documented simple and non-equilibrium turbulent flows. Finally, the current model provides a proposal to compute free shear flows.

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Keywords

coefficient of eddy-viscosity, cubic equation, k-equation model, production-to-dissipation ratio, turbulence anisotropy, REYNOLDS-STRESS, ARTIFICIAL COMPRESSIBILITY METHOD, TURBULENCE, FLOWS, EXPLICIT, HOT-WIRE, EPSILON

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DOI

10.1080/14685248.2019.1567926

Citation

Rahman, M M, Keskinen, K, Vuorinen, V, Larmi, M & Siikonen, T 2019, 'Consistently formulated eddy-viscosity coefficient for k-equation model', Journal of Turbulence, vol. 19, no. 11-12, pp. 959-994. https://doi.org/10.1080/14685248.2019.1567926

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https://urn.fi/URN:NBN:fi:aalto-201902252066

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[article-cris] Insinööritieteiden korkeakoulu / ENG