Journal ArticleDOI
On nonlinear K-l and K-ε models of turbulence
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TLDR
In this paper, a nonlinear K-l and K-e model is proposed to predict the normal Reynolds stresses in turbulent channel flow much more accurately than the linear model, and the nonlinear model is shown to be capable of predicting turbulent secondary flows in non-circular ducts.Abstract:
The commonly used linear K-l and K-e models of turbulence are shown to be incapable of accurately predicting turbulent flows where the normal Reynolds stresses play an important role. By means of an asymptotic expansion, nonlinear K-l and K-e models are obtained which, unlike all such previous nonlinear models, satisfy both realizability and the necessary invariance requirements. Calculations are presented which demonstrate that this nonlinear model is able to predict the normal Reynolds stresses in turbulent channel flow much more accurately than the linear model. Furthermore, the nonlinear model is shown to be capable of predicting turbulent secondary flows in non-circular ducts - a phenomenon which the linear models are fundamentally unable to describe. An additional application of this model to the improved prediction of separated flows is discussed briefly along with other possible avenues of future research.read more
Citations
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Journal ArticleDOI
Evaluation of Nonlinear κ-ε Models on Prediction Performance of Turbulence-Driven Secondary Flows
TL;DR: In this article, the authors evaluated the nonlinear relationship between Reynolds stresses and the rate of strain of nonlinear k-models by using the boundary layer assumptions against the turbulence-driven secondary flows in noncircular ducts and then their prediction performance was validated numerically through the application to the fully developed turbulent flow in a square duct.
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Supersonic Compression Ramp Flow. Synthesis of Results.
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Journal ArticleDOI
Invariant-based calibration of coefficients in nonlinear eddy viscosity turbulence closure
TL;DR: In this article, a nonlinear eddy viscosity turbulence closure is developed based on the standard quasi-linear pressure-strain correlation model, which adapts to flow conditions described by the invariants of mean-flow deformation and Reynolds stress anisotropy.
Journal ArticleDOI
Average Turbulence Dynamics from a One-Parameter Kinetic Theory
TL;DR: In this article , the mean turbulent dynamics can be described by a kinetic theory representation with a single free relaxation time that depends on space and time, and the dynamics of turbulent fluctuations resembles a collision process that asymptotically drives the mean distribution towards a Gaussian (Maxwell-Boltzmann) equilibrium form.
Fractional and tempered fractional models for Reynolds-averaged Navier-Stokes equations
TL;DR: In this article , the authors formulate a fractional stress-strain relationship using variable-order Caputo fractional derivative, where a non-constant diffusivity is introduced, which is characteristic of non-Fickian diffusion equation addressing anomalous diffusion process.
References
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Journal ArticleDOI
Progress in the development of a Reynolds-stress turbulence closure
TL;DR: In this article, the authors developed a model of turbulence in which the Reynolds stresses are determined from the solution of transport equations for these variables and for the turbulence energy dissipation rate E. Particular attention is given to the approximation of the pressure-strain correlations; the forms adopted appear to give reasonably satisfactory partitioning of the stresses both near walls and in free shear flows.
Journal ArticleDOI
A numerical study of three-dimensional turbulent channel flow at large Reynolds numbers
TL;DR: In this article, the three-dimensional, primitive equations of motion have been integrated numerically in time for the case of turbulent, plane Poiseuille flow at very large Reynolds numbers.
Journal ArticleDOI
Numerical investigation of turbulent channel flow
Parviz Moin,John Kim +1 more
TL;DR: In this article, a large-scale flow field was obtained by directly integrating the filtered, three-dimensional, time dependent, Navier-Stokes equations, and small-scale field motions were simulated through an eddy viscosity model.
Book ChapterDOI
Computational Modeling of Turbulent Flows
TL;DR: In this article, it is shown that direct simulation is not an alternative for practical computation and that the various sophisticated closures suffer from essentially the same problems as the direct simulations and therefore, are limited to homogeneous situations.
Journal ArticleDOI
A Reynolds stress model of turbulence and its application to thin shear flows
Kemal Hanjalic,Brian Launder +1 more
TL;DR: In this paper, the authors provided a model of turbulence which effects closure through approximated transport equations for the Reynolds stress tensor the turbulence energy κ and e.g., the turbulent shear stress does not vanish where the mean rate of strain goes to zero.