Journal ArticleDOI
A dynamic subgrid‐scale eddy viscosity model
TLDR
In this article, a new eddy viscosity model is presented which alleviates many of the drawbacks of the existing subgrid-scale stress models, such as the inability to represent correctly with a single universal constant different turbulent fields in rotating or sheared flows, near solid walls, or in transitional regimes.Abstract:
One major drawback of the eddy viscosity subgrid‐scale stress models used in large‐eddy simulations is their inability to represent correctly with a single universal constant different turbulent fields in rotating or sheared flows, near solid walls, or in transitional regimes. In the present work a new eddy viscosity model is presented which alleviates many of these drawbacks. The model coefficient is computed dynamically as the calculation progresses rather than input a priori. The model is based on an algebraic identity between the subgrid‐scale stresses at two different filtered levels and the resolved turbulent stresses. The subgrid‐scale stresses obtained using the proposed model vanish in laminar flow and at a solid boundary, and have the correct asymptotic behavior in the near‐wall region of a turbulent boundary layer. The results of large‐eddy simulations of transitional and turbulent channel flow that use the proposed model are in good agreement with the direct simulation data.read more
Citations
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Long-range sediment transport in the world’s oceans by stably stratified turbidity currents
TL;DR: In this article, the authors present numerical evidence that turbidity currents traveling on low slopes and carrying fine particles have a stably stratified shear layer along their upper interface, which dramatically reduces dissipation and entrainment of ambient fluid, allowing the current to propagate over long distances.
Journal ArticleDOI
LES analysis of turbulent boundary layer over 3D steep hill covered with vegetation
TL;DR: In this paper, a large eddy simulation (LES) was carried out to investigate the turbulent boundary-layer type of flows over a hill-shaped model with a steep slope.
Journal ArticleDOI
Prediction of turbulent separation over a backward-facing smooth ramp
B. Wasistho,Kyle D. Squires +1 more
TL;DR: In this paper, large eddy simulation (LES) and Reynolds-averaged Navier-Stokes (RANS) calculations have been performed of the turbulent flow over a smoothly contoured ramp.
Journal ArticleDOI
Influence of permeable beds on hydraulically macro-rough flow
TL;DR: In this article, the influence of bed permeability on the turbulence dynamics and structure is investigated, and it was observed that the scales of the spanwise vortical structures over more permeable granular beds are larger than those over less permeable beds.
Journal ArticleDOI
Dynamic structure subgrid‐scale models for large eddy simulation
TL;DR: In this article, a new one-equation large eddy simulation (LES) model is proposed based on separation of variable of interest into two parts-resolved and subgrid, and the effect of the subgrid part is modelled using subgrid-scale (SGS) models.
References
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Journal ArticleDOI
General circulation experiments with the primitive equations
TL;DR: In this article, an extended period numerical integration of a baroclinic primitive equation model has been made for the simulation and the study of the dynamics of the atmosphere's general circulation, and the solution corresponding to external gravitational propagation is filtered by requiring the vertically integrated divergence to vanish identically.
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Turbulence statistics in fully developed channel flow at low reynolds number
TL;DR: In this article, a direct numerical simulation of a turbulent channel flow is performed, where the unsteady Navier-Stokes equations are solved numerically at a Reynolds number of 3300, based on the mean centerline velocity and channel half-width, with about 4 million grid points.
Journal ArticleDOI
Renormalization group analysis of turbulence I. Basic theory
Victor Yakhot,Steven A. Orszag +1 more
TL;DR: In this article, a dynamic renormalization group (RNG) method for hydrodynamic turbulence was developed, which uses dynamic scaling and invariance together with iterated perturbation methods, allowing us to evaluate transport coefficients and transport equations for the large scale (slow) modes.
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.
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On Turbulent Flow Near a Wall
TL;DR: In this paper, the authors defined the distance from wall pipe radius pipe diameter mean local velocity parallel to wall velocity fluctuations parallel and normal to flow mass density coefficient of viscosity shear stress velocity correlation coefficient mixing length universal constant in I = Ky modified universal constant eddy viscosities size of roughness friction factor = 8rw/p V 2