A study of built-in filter for some eddy viscosity models in large-eddy simulation

2008 ◽  
pp. 164-175
Author(s):  
J.-C. Magnient ◽  
P. Sagaut ◽  
M. Deville
Keyword(s):  
Large Eddy Simulation ◽  
Eddy Viscosity ◽  
Eddy Simulation ◽  
Viscosity Models ◽  
Large Eddy

High-Pass Filtered Eddy-Viscosity Models for Large-Eddy Simulations of Compressible Wall-Bounded Flows

2005 ◽  
Vol 127 (4) ◽  
pp. 666-673 ◽  
Author(s):  
Steffen Stolz
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Large Eddy Simulation ◽  
Eddy Viscosity ◽  
Correct Prediction ◽  
Smagorinsky Model ◽  
Eddy Simulation ◽  
Viscosity Models ◽  
Large Eddy ◽  
High Pass

In this contribution we consider large-eddy simulation (LES) using the high-pass filtered (HPF) Smagorinsky model of a spatially developing supersonic turbulent boundary layer at a Mach number of 2.5 and momentum-thickness Reynolds numbers at inflow of ∼4500. The HPF eddy-viscosity models employ high-pass filtered quantities instead of the full velocity field for the computation of the subgrid-scale (SGS) model terms. This approach has been proposed independently by Vreman (Vreman, A. W., 2003, Phys. Fluids, 15, pp. L61–L64) and Stolz et al. (Stolz, S., Schlatter, P., Meyer, D., and Kleiser, L., 2003, in Direct and Large Eddy Simulation V, Kluwer, Dordrecht, pp. 81–88). Different from classical eddy-viscosity models, such as the Smagorinsky model (Smagorinsky, J., 1963, Mon. Weath. Rev, 93, pp. 99–164) or the structure-function model (Métais, O. and Lesieur, M., 1992, J. Fluid Mech., 239, pp. 157–194) which are among the most often employed SGS models for LES, the HPF eddy-viscosity models do need neither van Driest wall damping functions for a correct prediction of the viscous sublayer of wall-bounded turbulent flows nor a dynamic determination of the coefficient. Furthermore, the HPF eddy-viscosity models are formulated locally and three-dimensionally in space. For compressible flows the model is supplemented by a HPF eddy-diffusivity ansatz for the SGS heat flux in the energy equation. Turbulent inflow conditions are generated by a rescaling and recycling technique in which the mean and fluctuating part of the turbulent boundary layer at some distance downstream of inflow is rescaled and reintroduced at the inflow position (Stolz, S. and Adams, N. A., 2003, Phys. Fluids, 15, pp. 2389–2412).

A study of built-in filter for some eddy viscosity models in large-eddy simulation

2001 ◽  
Vol 13 (5) ◽  
pp. 1440-1449 ◽  
Author(s):  
Jean-Christophe Magnient ◽  
Pierre Sagaut ◽  
Michel Deville
Keyword(s):  
Large Eddy Simulation ◽  
Eddy Viscosity ◽  
Eddy Simulation ◽  
Viscosity Models ◽  
Large Eddy

scholarly journals Large eddy simulation model for wind-driven sea circulation in coastal areas

2013 ◽  
Vol 20 (6) ◽  
pp. 1095-1112 ◽  
Author(s):  
A. Petronio ◽  
F. Roman ◽  
C. Nasello ◽  
V. Armenio
Keyword(s):  
Large Eddy Simulation ◽  
Simulation Model ◽  
Water Column ◽  
Eddy Viscosity ◽  
Vertical Mixing ◽  
Water Circulation ◽  
Bottom Surface ◽  
Large Eddy Simulation Model ◽  
Eddy Simulation ◽  
Large Eddy

Abstract. In the present paper a state-of-the-art large eddy simulation model (LES-COAST), suited for the analysis of water circulation and mixing in closed or semi-closed areas, is presented and applied to the study of the hydrodynamic characteristics of the Muggia bay, the industrial harbor of the city of Trieste, Italy. The model solves the non-hydrostatic, unsteady Navier–Stokes equations, under the Boussinesq approximation for temperature and salinity buoyancy effects, using a novel, two-eddy viscosity Smagorinsky model for the closure of the subgrid-scale momentum fluxes. The model employs: a simple and effective technique to take into account wind-stress inhomogeneity related to the blocking effect of emerged structures, which, in turn, can drive local-scale, short-term pollutant dispersion; a new nesting procedure to reconstruct instantaneous, turbulent velocity components, temperature and salinity at the open boundaries of the domain using data coming from large-scale circulation models (LCM). Validation tests have shown that the model reproduces field measurement satisfactorily. The analysis of water circulation and mixing in the Muggia bay has been carried out under three typical breeze conditions. Water circulation has been shown to behave as in typical semi-closed basins, with an upper layer moving along the wind direction (apart from the anti-cyclonic veering associated with the Coriolis force) and a bottom layer, thicker and slower than the upper one, moving along the opposite direction. The study has shown that water vertical mixing in the bay is inhibited by a large level of stable stratification, mainly associated with vertical variation in salinity and, to a minor extent, with temperature variation along the water column. More intense mixing, quantified by sub-critical values of the gradient Richardson number, is present in near-coastal regions where upwelling/downwelling phenomena occur. The analysis of instantaneous fields has detected the presence of large cross-sectional eddies spanning the whole water column and contributing to vertical mixing, associated with the presence of sub-surface horizontal turbulent structures. Analysis of water renewal within the bay shows that, under the typical breeze regimes considered in the study, the residence time of water in the bay is of the order of a few days. Finally, vertical eddy viscosity has been calculated and shown to vary by a couple of orders of magnitude along the water column, with larger values near the bottom surface where density stratification is smaller.

Evaluation of Turbulence Models Using Direct Numerical and Large-Eddy Simulation Data

2011 ◽  
Vol 133 (2) ◽  
Author(s):  
Hassan Raiesi ◽  
Ugo Piomelli ◽  
Andrew Pollard
Keyword(s):  
Boundary Layer ◽  
Large Eddy Simulation ◽  
Eddy Viscosity ◽  
Predictive Accuracy ◽  
Turbulence Models ◽  
Special Treatment ◽  
Two Dimensional ◽  
Square Duct ◽  
Eddy Simulation ◽  
Large Eddy

The performance of some commonly used eddy-viscosity turbulence models has been evaluated using direct numerical simulation (DNS) and large-eddy simulation (LES) data. Two configurations have been tested, a two-dimensional boundary layer undergoing pressure-driven separation, and a square duct. The DNS and LES were used to assess the k−ε, ζ−f, k−ω, and Spalart–Allmaras models. For the two-dimensional separated boundary layer, anisotropic effects are not significant and the eddy-viscosity assumption works well. However, the near-wall treatment used in k−ε models was found to have a critical effect on the predictive accuracy of the model (and, in particular, of separation and reattachment points). None of the wall treatments tested resulted in accurate prediction of the flow field. Better results were obtained with models that do not require special treatment in the inner layer (ζ−f, k−ω, and Spalart–Allmaras models). For the square duct calculation, only a nonlinear constitutive relation was found to be able to capture the secondary flow, giving results in agreement with the data. Linear models had significant error.

A Large Eddy Simulation of the Bubbly Flow in Vertical Tube

2012 ◽  
Author(s):  
Peng Zhang ◽  
Xu Hong
Keyword(s):  
Large Eddy Simulation ◽  
Eddy Viscosity ◽  
Bubbly Flow ◽  
Turbulence Models ◽  
Vertical Tube ◽  
Simulation Approach ◽  
Bubble Distribution ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Two Fluid

This paper simulates the dispersed bubbly flow in a vertical tube with two different turbulence models based on Eulerian two-fluid frameworks. Both the RANS (Reynolds Averaged N-S equation) approach and LES (Large Eddy Simulation) approach can get results agreed with experiment well. The “wall peak” bubble distribution is captured. Compare with RANS with SST (Shear Stress Transport) turbulence model, the LES with WALE (Wall-Adapted Local Eddy-viscosity) sub-grid model can give transient and detail information of the flow field, and it shows better agreement.

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