Direct Numerical Simulation analysis of the Flame Surface Density transport equation in the context of Large Eddy Simulation

2009 ◽  
Vol 32 (1) ◽  
pp. 1445-1453 ◽  
Author(s):  
Nilanjan Chakraborty ◽  
R.S. Cant
Keyword(s):  
Numerical Simulation ◽  
Large Eddy Simulation ◽  
Direct Numerical Simulation ◽  
Transport Equation ◽  
Surface Density ◽  
Simulation Analysis ◽  
Flame Surface ◽  
Flame Surface Density ◽  
Eddy Simulation ◽  
Large Eddy

scholarly journals A PrioriDirect Numerical Simulation Modelling of the Curvature Term of the Flame Surface Density Transport Equation for Nonunity Lewis Number Flames in the Context of Large Eddy Simulations

2012 ◽  
Vol 2012 ◽  
pp. 1-14 ◽  
Author(s):  
Mohit Katragadda ◽  
Nilanjan Chakraborty
Keyword(s):  
Numerical Simulation ◽  
Transport Equation ◽  
Surface Density ◽  
Lewis Number ◽  
Simulation Modelling ◽  
Flame Surface ◽  
Flame Surface Density ◽  
Curvature Term ◽  
Wide Range ◽  
Large Eddy

A Direct Numerical Simulation (DNS) database of freely propagating statistically planar turbulent premixed flames with Lewis numbersLeranging from 0.34 to 1.2 has been used to analyse the statistical behaviours of the curvature term of the generalised Flame surface Density (FSD) transport equation, in the context of the Large Eddy Simulation (LES). Lewis number is shown to have significant influences on the statistical behaviours of the resolved and sub-grid parts of the FSD curvature term. It has been found that the existing models for the sub-grid curvature termCsgdo not capture the qualitative behaviour of this term extracted from the DNS database for flames withLe<<1. The existing models ofCsgonly predict negative values, whereas the sub-grid curvature term is shown to assume positive values within the flame brush for theLe=0.34and 0.6 flames. Here the sub-grid curvature terms arising from combined reaction and normal diffusion and tangential diffusion components of displacement speed are individually modelled, and the new model of the sub-grid curvature term has been found to captureCsgextracted from DNS data satisfactorily for all the different Lewis number flames considered here for a wide range of filter widths.

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