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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Journal ArticleDOI
Towards a new partially integrated transport model for coarse grid and unsteady turbulent flow simulations
TL;DR: In this paper, a two-equation model is proposed for large eddy simulations (LESs) using coarse grids, where the modeled transport equations are obtained from a direct transposition of well-known statistical models by using multiscale spectrum splitting given by the filtering operation applied to the Navier-Stokes equations.
Journal ArticleDOI
Image-based large-eddy simulation in a realistic left heart
TL;DR: In this article, a numerical framework allowing insight in fluid dynamics inside patient-specific human hearts is presented, where the heart cavities and their wall dynamics are extracted from medical images, with the help of a non-linear image registration algorithm, in order to obtain a patient specific moving numerical domain.
Journal ArticleDOI
Large eddy simulation of the flow around a low-rise building immersed in a rough-wall turbulent boundary layer
Kojiro Nozawa,Tetsuro Tamura +1 more
TL;DR: In this paper, a half-height cube was immersed in the turbulent boundary layers with several types of vertical velocity profile and the peak pressure distributions on the surface of the half height cube were computed.
Journal ArticleDOI
Hybrid Simulation Approach for Cavity Flows: Blending, Algorithm, and Boundary Treatment Issues
TL;DR: A new hybrid approach is discussed, where the transition between these equation sets is controlled by a blending function that depends on local turbulent flow properties, as well as the local mesh spacing, to enhance the capturing of large eddy motions.
Journal ArticleDOI
Development of filtered Euler–Euler two-phase model for circulating fluidised bed: High resolution simulation, formulation and a priori analyses
TL;DR: In this article, a priori analyses on the filtered phase balance equations are performed for a 3D periodic circulating fluidised bed. But the results do not account for the particle segregation effect at the small scale and this causes poor prediction of bed hydrodynamics.
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.
Journal ArticleDOI
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.
Journal ArticleDOI
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