In this study, turbulent flow around a tube bundle in non-orthogonal grid is simulated using the Large Eddy Simulation (LES) technique and parallelization of fully coupled Navier – Stokes (NS) equations. To model the small eddies, the Smagorinsky and a mixed model was used. This model represents the effect of dissipation and the grid-scale and subgrid-scale interactions. The fully coupled NS eq...

This paper introduces a new approach to Large-Eddy Simulation (LES) where subgrid-scale (SGS) dissipation is applied proportionally to the degree of local spectral broadening, hence mitigated or deactivated in regions dominated by large-scale and/or laminar vortical motion. The proposed coherentvorticity preserving (CvP) LES methodology is based on the evaluation of the ratio of the test-filter...

Since its rst application, the dynamic procedure has been recognized as an eeec-tive means to compute rather than prescribe the unknown coeecients that appear in a subgrid-scale model for Large-Eddy Simulation (LES). The dynamic procedure (Germano et al. 1991; Ghosal et al. 1995) is usually used to determine the non-dimensional coeecient in the Smagorinsky (1963) model. In reality the procedure...

In this paper the large eddy simulation (LES) and conditional moment closure (CMC) combustion model have been applied for modelling of auto-ignition of hydrogen jet issuing into a hot ambient co-flow. Most of the attention was devoted to modelling aspects of the conditional scalar dissipation rate which is a key quantity of the CMC model. Two models are compared with emphasis on differences in ...

A three-dimensional mathematical model has been developed for the simulation of flow, temperature and concentration fields in the radiation section of industrial scale steam cracking units. The model takes into account turbulence–chemistry interactions through the Eddy Dissipation Concept (EDC) model and makes use of Detailed Reaction Kinetics (DRK), which allows the detailed investigation of t...

LES models for subgrid scalar transport and dissipation are assessed through joint experimental and numerical studies using experimental data from an axisymmetric, turbulent, co-flowing jet, and large eddy simulation of scalar mixing in a round turbulent jet. The dissipation models tested include: a gradient-based model, which is based on a local equilibrium assumption, a model that assumes pro...

HPIV measurements of a turbulent flow in a square duct are used for studying the 3-D geometric relations between SGS stresses, filtered strain-rates and vorticity. Conditional sampling is performed based on the strain-rate magnitude and SGS dissipation, including negative values. In regions of high dissipation, the flow is more likely to be in axisymmetric expansion with vorticity strongly alig...

Significant electron density striations, neutral temperatures 27 K above nominal, and intense wind shear were observed in the E-region ionosphere over the Jicamarca Radio Observatory during an unusual event on 26 July 2005 (Hysell et al., 2007). In this paper, these results are used to estimate eddy turbulence parameters and their effects. Models for the thermal balance in the mesosphere/lower ...

Occurrence of laminar separation bubbles on solid walls of an elliptic cylinder has been simulated using a recently developed transitional model for boundary layer flows. Computational method is based on the solution of the Reynolds averaged Navier-Stokes (RANS) equations and the eddy-viscosity concept. Transitional model tries to simulate streamwise fluctuations, induced by freestream turbulen...