A modified selective structure function subgrid-scale model

A modified-Leray-α subgrid scale model of turbulence

Inspired by the remarkable performance of the Leray-α (and the Navier–Stokes alpha (NS-α), also known as the viscous Camassa–Holm) subgrid scale model of turbulence as a closure model to Reynolds averaged equations (RANS) for flows in turbulent channels and pipes, we introduce in this paper another subgrid scale model of turbulence, the modified Leray-α (ML-α) subgrid scale model of turbulence....

A velocity-estimation subgrid model constrained by subgrid scale dissipation

Purely dissipative eddy–viscosity subgrid models have proven very successful in large–eddy simulations (LES) at moderate resolution. Simulations at coarse resolutions where the underlying assumption of small–scale universality is not valid, warrant more advanced models. However, non-eddy viscosity models are often unstable due to the lack of sufficient dissipation. This paper proposes a simple ...

Modified Structure Function Model Based on Coherent Structures

In the present study, a modified Structure Function was introduced. In this modified Structure Function model, the coefficient of model was computed dynamically base on the coherent structure in the flow field. The ability of this Modified Structure Function was investigated for complex flow over a square cylinder in free stream and a low aspect ratio cylinder confined in a channel. The Results...

Subgrid-scale model tests using petascale computers

Large-eddy simulation (LES) has become an effective research tool for the atmospheric bound¬ary layer (ABL) and probably the most in the atmospheric surface layer LES suffers from inherent underresolution and poor subgrid-scale (SGS) model performance. To develop improved SGS models a methodology for testing model perfor¬mance is needed. Previous tests rely on comparing the modeled and measured...

A Discrete Dynamical System Subgrid-Scale Model of Turbulent Convection