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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Effects of the injection parameters and compression ratio on the emissions of a heavy-duty diesel engine
TL;DR: In this article, homogenous charge compression ignition (HCCI) cases are compared for improvements on the combustion chamber design of the engine to achieve near zero particulate matter (PM) and NOx emissions.
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Modeling of compressible effects on the Reynolds stress using a Markovianized two-scale method
TL;DR: In this paper, the authors modeled compressibility effects on the Reynolds stress using a Markovianized two-scale method using a simple model with the former compressibility effect incorporated is applied to fully developed free shear layers and is shown to capture the steep decrease in the growth rate with the increasing convective Mach number.
Journal ArticleDOI
Large-eddy simulation of turbulent heat convection in a spanwise rotating channel flow
TL;DR: In this paper, the effects of the Coriolis force in a heated plane channel flow subjected to spanwise rotation using the method of large-eddy simulation are investigated, and both the general and simplified transport equations for the resolved turbulent stresses, which are essential for understanding the unique pattern of turbulent kinetic energy production in a rotating system.
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Simulations of laminar and turbulent flows over periodic hills with immersed boundary method
TL;DR: In this article, an immersed boundary method was used to simulate laminar and turbulent flows over periodic hills with and without wall models, and the results showed that with wall models the recirculation zone and excessive diffusive transport across the shear layer were faster than with no wall models.
Journal ArticleDOI
A rate-dependent algebraic stress model for turbulence
TL;DR: In this paper, a rate-dependent algebraic expression for the Reynolds stress tensor is developed based on the stress transport model, which includes the normal stress effects and exhibits viscoelastic behavior.
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.