Modeling dilute sediment suspension using large-eddy simulation with a dynamic mixed model

2008 ◽  
Vol 20 (11) ◽  
pp. 115103 ◽  
Author(s):  
Yi-Ju Chou ◽  
Oliver B. Fringer
Keyword(s):  
Large Eddy Simulation ◽  
Mixed Model ◽  
Sediment Suspension ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Dynamic Mixed Model

Large Eddy Simulation of the Flow and Heat Transfer in a Matrix of Cubes

2014 ◽  
Author(s):  
Paolo Lampitella ◽  
Riccardo Mereu ◽  
Emanuela Colombo ◽  
Fabio Inzoli
Keyword(s):  
Heat Transfer ◽  
Mixed Model ◽  
Scale Model ◽  
Heat Transfer Characteristics ◽  
Smagorinsky Model ◽  
Classical Dynamic ◽  
Eddy Simulation ◽  
Flow And Heat Transfer ◽  
Large Eddy ◽  
Dynamic Mixed Model

This work presents Large Eddy Simulations of the flow and heat transfer characteristics in a matrix of surface mounted cubes, studying the effect of the grid resolution and the sub-grid scale modeling. Three sub-grid scale models, implemented in an unstructured, finite volume, commercial solver, are compared on four different grids in terms of first and second order statistical quantities. A classical Dynamic Smagorinsky model is compared with a no-model, Implicit Large Eddy Simulation, approach and a recently developed, two parameters, dynamic-mixed model. A general lack of sensitivity to the sub-grid scale model is evidenced for the flow quantities at all the resolutions, but the grid design emerges as the most determining factor for this kind of flows, showing that accurate results are possible with very coarse resolutions. In contrast, heat transfer characteristics show a strong dependence on both the grid and the sub-grid scale model with a lack of clear convergence in the investigated range of scales. The dynamic-mixed model, which for the first time is tested in a heat-transfer application, is found stable on strongly stretched grids and cheaper than the classical Dynamic Smagorinsky model due to its specific finite volume formulation, showing its suitability for more complex applications.

scholarly journals Improving Large-Eddy Simulation of Neutral Boundary Layer Flow across Grid Interfaces

2015 ◽  
Vol 143 (8) ◽  
pp. 3310-3326 ◽  
Author(s):  
Elijah Goodfriend ◽  
Fotini Katopodes Chow ◽  
Marcos Vanella ◽  
Elias Balaras
Keyword(s):  
Boundary Layer ◽  
Large Eddy Simulation ◽  
Atmospheric Boundary Layer ◽  
Adaptive Mesh Refinement ◽  
Mixed Model ◽  
Adaptive Mesh ◽  
Grid Refinement ◽  
Eddy Simulation ◽  
Advection Term ◽  
Large Eddy

Abstract Increasing computational power has enabled grid resolutions that support large-eddy simulation (LES) of the atmospheric boundary layer. These simulations often use grid nesting or adaptive mesh refinement to refine the grid in regions of interest. LES generates errors at grid refinement interfaces, such as resolved energy accumulation, that may compromise solution accuracy. In this paper, the authors test the ability of two LES formulations and turbulence closures to mitigate errors associated with the use of LES on nonuniform grids for a half-channel approximation to a neutral atmospheric boundary layer simulation. Idealized simulations are used to examine flow across coarse–fine and fine–coarse interfaces, as would occur in a two-way nested configuration or with block structured adaptive mesh refinement. Specifically, explicit filtering of the advection term and the mixed model are compared to a standard LES formulation with an eddy viscosity model. Errors due to grid interfaces are evaluated by comparison to uniform grid solutions. It is found that explicitly filtering the advection term provides significant benefits, in that it allows both mass and momentum to be conserved across grid refinement interfaces. The mixed model reduces unphysical perturbations generated by wave reflection at the interfaces. These results suggest that the choice of LES formulation and turbulence closure can be used to help control grid refinement interface errors in atmospheric boundary layer simulations.

A compressible wall-adapting similarity mixed model for large-eddy simulation of the impinging round jet

2009 ◽  
Vol 21 (3) ◽  
pp. 035102 ◽  
Author(s):  
Guido Lodato ◽  
Luc Vervisch ◽  
Pascale Domingo
Keyword(s):  
Large Eddy Simulation ◽  
Mixed Model ◽  
Round Jet ◽  
Eddy Simulation ◽  
Large Eddy
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