Following the relative success of mixed models in Large Eddy Simulation complex turbulent flow configurations, an alternative formulation is suggested here which incorporates concept a local subgrid activity sensor. The general idea to combine advantages structural (superior alignment properties), usually scale similarity type, and functional stability), eddy viscosity while avoiding their disa...

We explore the utility of the recently proposed alpha equations in providing a subgrid model for fluid turbulence. Our principal results are comparisons of direct numerical simulations of fluid turbulence using several values of the parameter alpha, including the limiting case where the Navier-Stokes equations are recovered. Our studies show that the large scale features, including statistics a...

Consider the macroscale modelling of microscale spatiotemporal dynamics. Here we develop a new approach to ensure coarse scale discrete models preserve important self-adjoint properties of the fine scale dynamics. The first part explores the discretisation of microscale continuum dynamics. The second addresses how dynamics on a fine lattice are mapped to lattice a factor of two coarser (as in m...

The α-modeling strategy is followed to derive a new subgrid parameterization of the turbulent stress tensor in large-eddy simulation (LES). The LES-α modeling yields an explicitly filtered subgrid parameterization which contains the filtered nonlinear gradient model as well as a model which represents ‘Leray-regularization’. The LES-α model is compared with similarity and eddy-viscosity models ...

A review of existing basic turbulence modeling approaches reveals the need for the development of unified turbulence models which can be used continuously as filter density function (FDF) or probability density function (PDF) methods, large eddy simulation (LES) or Reynolds-averaged Navier–Stokes (RANS) methods. It is then shown that such unified stochastic and deterministic turbulence models c...

Clouds exhibit spatial variability on a range of scales, and this variability influences microphysical processes such as drizzle formation (Pincus and Klein 2000; Larson et al. 2001). For this and other reasons, large-scale models may benefit from including the effects of subgrid cloud variability on microphysical process rates. For instance, feeding the fraction of a grid box occupied by cloud...

In this paper, the present state of the large-eddy simulation (LES) technique is discussed. Modeling and numerical issues that are under study will be described, and results of state-of-the-art calculations will be presented to highlight the response of the subgrid-scale models to important features of the flow field. Finally, some challenges for research and applications of LES in the near fut...

We present a one-equation subgrid scale model that evolves the turbulence energy corresponding to unresolved velocity fluctuations in large eddy simulations. The model is derived in the context of the Germano consistent decomposition of the hydrodynamical equations. The eddy-viscosity closure for the rate of energy transfer from resolved toward subgrid scales is localised by means of a dynamica...

Swirling flames are widely used in engineering to intensify mixing and stabilize combustion gas turbine power plants industrial burners. induces new instability modes, leading intensification of coherent structures, asymmetric geometry, vortex core precession, flame oscillations. Large-Eddy Simulation (LES) has the capability furnish more accurate reliable results than simulations based on Reyn...