Proper representation of the subgrid-scale eddy viscosity for the dynamic procedure in large eddy simulation using finite difference method

2001 ◽  
Vol 13 (2) ◽  
pp. 500-504 ◽  
Author(s):  
Makoto Tsubokura
Keyword(s):  
Finite Difference ◽  
Finite Difference Method ◽  
Large Eddy Simulation ◽  
Difference Method ◽  
Eddy Viscosity ◽  
Subgrid Scale ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Proper Representation

Validation of a Three-Dimensional Large Eddy Simulation Finite Difference Method to Study Vortex Induced Vibration

2006 ◽  
Author(s):  
Paulo T. Esperanc¸a ◽  
Juan B. V. Wanderley ◽  
Carlos Levi
Keyword(s):  
Experimental Data ◽  
Finite Difference ◽  
Finite Difference Method ◽  
Large Eddy Simulation ◽  
Difference Method ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Vortex Induced Vibration ◽  
Eddy Simulation ◽  
Large Eddy

Two-dimensional numerical simulations of Vortex Induced Vibration have been failing to duplicate accurately the corresponding experimental data. One possible explanation could be 3D effects present in the real problem that are not modeled in two-dimensional simulations. A three-dimensional finite difference method was implemented using Large Eddy Simulation (LES) technique and Message Passage Interface (MPI) and can be run in a cluster with an arbitrary number of computers. The good agreement with other numerical and experimental data obtained from the literature shows the good quality of the implemented code.

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

2007 ◽  
Author(s):  
Donghyun You ◽  
Parviz Moin
Keyword(s):  
Large Eddy Simulation ◽  
Eddy Viscosity ◽  
Viscosity Model ◽  
Scale Model ◽  
Complex Geometries ◽  
Subgrid Scale ◽  
Eddy Simulation ◽  
Eddy Viscosity Model ◽  
Large Eddy ◽  
Model Coefficient

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.

Large Eddy Simulation of Rotating Finite Source Convection

2005 ◽  
Vol 73 (1) ◽  
pp. 79-87
Author(s):  
Shari J. Kimmel-Klotzkin ◽  
Fadi P. Deek
Keyword(s):  
Large Eddy Simulation ◽  
Eddy Viscosity ◽  
Rotating Flows ◽  
Scale Model ◽  
Subgrid Scale ◽  
Smagorinsky Model ◽  
Convective Flows ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Subgrid Scale Model

Numerical simulations of turbulent convection under the influence of rotation will help understand mixing in oceanic flows. Though direct numerical simulations (DNS) can accurately model rotating convective flows, this method is limited to small scale and low speed flows. A large eddy simulation (LES) with the Smagorinsky subgrid scale model is used to compute the time evolution of a rotating convection flow generated by a buoyancy source of finite size at a relatively high Rayleigh number. Large eddy simulations with eddy viscosity models have been used successfully for other rotating convective flows, so the Smagorinsky model is a reasonable starting point. These results demonstrate that a LES can be used to model larger scale rotating flows, and the resulting flow structure is in good agreement with DNS and experimental results. These results also demonstrate that the qualitative behavior of vorticies which form under the source depend on the geometry of the flow. For source diameters that are small compared to the size of the domain, the vortices propagate away from the source. On the other hand, if the ratio of source diameter to domain size is relatively large, the vortices are constrained beneath the source. Though the results are qualitatively similar to a direct numerical simulation (DNS) and other LES, in this simulation the flow remains laminar much longer than the DNS predicts. This particular flow is complicated by the turbulence transition between the convective plume and the quiescent ambient fluid, and an eddy viscosity model is inadequate to accurately model this type of flow. In addition, the Smagorinsky model is not consistent in a noninertial reference frame. Thus the Smagorinsky model is not the optimal choice for this type of flow. In particular, the estimation model has demonstrated better results for other types of rotating flows and is the recommended subgrid scale model for future work.

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