Application of a Dynamic Global-Coefficient Subgrid-Scale Model for Large-Eddy Simulation in Complex Geometries

Author(s):  
Donghyun You ◽  
Parviz Moin

The application of a dynamic global-coefficient subgrid-scale eddy-viscosity model for large-eddy simulation in complex geometries is presented. The model employs a dynamic procedure for closure of the subgrid-scale eddy-viscosity model developed by Vreman [Phys. Fluids 16, 3670 (2004)]. The model coefficient which is globally constant in space but varies in time is dynamically determined assuming the “global equilibrium” between the subgrid-scale dissipation and the viscous dissipation of which utilization was proposed by Park et al. [Phys. Fluids 18, 125109 (2006)]. Like the Vreman’s model with a fixed coefficient and the dynamic-coefficient model of Park et al., the present model predicts zero eddy-viscosity in regions where the vanishing eddy viscosity is theoretically expected. The present dynamic model is especially suitable for large-eddy simulation in complex geometries since it does not require any ad hoc spatial and temporal averaging or clipping of the model coefficient for numerical stabilization and requires only a single-level test filter.

2013 ◽  
Vol 444-445 ◽  
pp. 1579-1591
Author(s):  
A.C.Y. Yuen ◽  
G.H. Yeoh ◽  
R.K.K. Yuen ◽  
S.M. Lo ◽  
T. Chen

The Wall Adpating Local Eddy Viscosity (WALE) subgrid-scale turbulence model was adopted for an in-house large eddy simulation (LES) fire code in which the turbulence is fully coupled combustion and radiation models. The traditional Smagorinsky subgrid-scale model accounts only strain rate of the turbulent structure while the WALE model considers both the strain and the rotation rates. Furthermore, the WALE model automatically recovers the near wall-scaling for the eddy viscosity hence more adaptive for wall bounded flows.A 15 m long test hall fire was reconstructed by the in-house fire code with 1.5 MW fire source. The performance of the WALE model was assessed by comparingpredicted transient gas temperatures and velocities at various spatial locations.


2011 ◽  
Vol 261-263 ◽  
pp. 837-841
Author(s):  
Wen Quan Wang ◽  
Yan Yan

In the present study, the dynamic Vreman model based on the global equilibrium between the subgrid-scale dissipation and the viscous dissipation with a global model coefficient are applied to large eddy simulation of turbulent flow in complex geometries. Distributions of pressure, velocity and vorticity as well as some flow structure are gained, which is helpful to examine the performance of SGS model and understand the flow characters in complex geometries.


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