The sensitivity of large-eddy simulation of turbulent shear flow to subgrid models

1994 ◽  
Vol 70 (1-2) ◽  
pp. 133-150 ◽  
Author(s):  
P. J. Mason ◽  
A. R. Brown
Keyword(s):  
Shear Flow ◽  
Large Eddy Simulation ◽  
Turbulent Shear ◽  
Turbulent Shear Flow ◽  
Eddy Simulation ◽  
Large Eddy

scholarly journals Large-eddy simulation of particle-laden turbulent flows

2008 ◽  
Vol 614 ◽  
pp. 207-252 ◽  
Author(s):  
M. BINI ◽  
W. P. JONES
Keyword(s):  
Liquid Phase ◽  
Large Eddy Simulation ◽  
Turbulent Flows ◽  
Large Scale ◽  
Isotropic Turbulence ◽  
Probabilistic Approach ◽  
Turbulent Shear ◽  
Turbulent Shear Flow ◽  
Eddy Simulation ◽  
Large Eddy

A large-eddy-based methodology for the simulation of turbulent sprays is discussed. The transport equations for the spatially filtered gas phase variables, in which source terms accounting for the droplet effects are added, are solved together with a probabilistic description of the liquid phase. The probabilistic approach for the liquid phase is based on the transport equation for the spatially filtered joint probability density function of the variables required in order to describe the state of the liquid phase. In this equation, unclosed terms representing the filtered Lagrangian rates of change of the variables describing the spray are present. General modelling ideas for subgrid-scale (SGS) effects are proposed. The capabilities of the approach and the validity of the closure models, with particular with respect to the SGS dispersion, are investigated through application to a dilute particle-laden turbulent mixing layer. It is demonstrated that the formulation is able to reproduce very closely the measured properties of both the continuous and dispersed phases. The large-eddy simulation (LES) results are also found to be entirely consistent with the experimentally observed characteristics of droplet–gas turbulence interactions. Consistent with direct numerical simulation (DNS) studies of isotropic turbulence laden with particles where the entire turbulence spectrum is found to be modulated by the presence of particles, the present investigation, which comprises the effects of particle transport upon the large-scale vortical structures of a turbulent shear flow, highlights what appears to be a selective behaviour; few large-scale frequencies gain energy whereas the remaining modes are damped.

Large Eddy Simulation of Leading Edge Film Cooling: Part II — Heat Transfer and Effect of Blowing Ratio

2007 ◽  
Author(s):  
Ali Rozati ◽  
Danesh K. Tafti
Keyword(s):  
Heat Transfer ◽  
Large Eddy Simulation ◽  
Film Cooling ◽  
Leading Edge ◽  
Turbulent Shear ◽  
Surface Distribution ◽  
Blowing Ratio ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Adiabatic Effectiveness

Detailed investigation of film cooling for a cylindrical leading edge is carried out using Large Eddy Simulation (LES). Part-II of the paper focuses on the effect of coolant to mainstream blowing ratio on flow features and consequently on the adiabatic effectiveness and heat transfer ratio. With the advantage of obtaining unique, accurate and dynamic results from LES, the influential coherent structures in the flow are identified. Describing the mechanism of jet – mainstream interaction, it is shown that as the blowing ratio increases, a more turbulent shear layer and stronger mainstream entrainment occur. The combined effect, leads to a lower adiabatic effectiveness and higher heat transfer coefficient. Surface distribution and span-averaged profiles are shown for both adiabatic effectiveness and heat transfer (presented by Frossling number). Results are in good agreement with the experimental data of Ekkad et al. [12].

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