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...

In large eddy simulation (LES) of turbulent flows, dynamic subgrid models would account for an average cascade kinetic energy from the largest to smallest scales flow. Yet, it is unclear which most critical dynamical processes can ensure criterion mentioned above. Furthermore, evidence vortex stretching being primary mechanism not out question. this article, we study essential statistical chara...

The dissipation rate transport equation remains the most uncertain part of turbulence modeling. The difficulties are increased when external agencies like rotation prevent straightforward dimensional analysis from determining the correct form of the modelled equation. In this work, the dissipation rate transport equation and subgrid scale models for rotating turbulence are derived from an analy...

[1] Using large-eddy simulations (LESs) of six observed boundary layer cases as benchmark data sets, we diagnosed vertical velocity as the sum of the grid-mean (w) and the subgrid-scale w using an empirical method we have developed. We have found that the subgrid-scale w is best characterized by the root-mean square of w02. The vertical velocity is expressed in the form of w = w + c ffiffiffiff...

Direct numerical simulations (DNS) of passive scalar mixing in isotropic turbulence is used to study, analyze and, subsequently, model the role of small (subgrid) scales in the mixing process. In particular, we attempt to model the dissipation of the large scale (supergrid) scalar uctuations caused by the subgrid scales by decomposing it into two parts: (i) the e ect due to the interaction amon...

Large-eddy simulation of combustion problems involves highly nonlinear terms that, when filtered, result in a contribution from subgrid fluctuations of scalars, Z, to the dynamics of the filtered value. This subgrid contribution requires modeling. Reconstruction models try to recover as much information as possible from the resolved field Z̄ , based on a deconvolution procedure to obtain an inte...

Large-eddy simulation of combustion problems involves highly nonlinear terms that, when filtered, result in a contribution from subgrid fluctuations of scalars, Z, to the dynamics of the filtered value. This subgrid contribution requires modeling. Reconstruction models try to recover as much information as possible from the resolved field Z ¯ , based on a deconvolution procedure to obtain an in...

The LES method is an attractive approach for the simulation of turbulent jet flames. In this method, the effects of large scale structures controlling the mixing process are resolved while small-scale effects such as the leading-edge flames involved in the flame base dynamics are accounted for by the subgrid-scale models. The LES approach is examined in this study with a particular emphasis on ...

The large eddy simulation equations of turbulent flows are formally derived by applying a low-pass filter to the Navier-Stokes equations. As a result the subgrid-scale stress tensor strongly depends on the assumed filter shape, which causes a subgrid scales model to be filter dependent. Depending on the choice of the filter, the corresponding model should satisfy very different requirements in ...