TY - GEN
T1 - Accuracy of large-eddy simulation of premixed turbulent combustion
AU - Vreman, A.W.
AU - Bastiaans, R.J.M.
AU - Geurts, B.J.
PY - 2008
Y1 - 2008
N2 - The accuracy of large-eddy simulation (LES) of a turbulent premixed Bunsen flame is investigated in this paper. To distinguish between discretization and modeling errors, multiple large-eddy simulations, using different grid size h but the same filterwidth ¿, are compared with the direct numerical simulation (DNS). In addition, large-eddy simulations using multiple ¿ but the same ratio ¿/h are compared. The chemistry in the LES and DNS is parametrized with the standard steady premixed flamelet for stochiometric methane-air combustion. The subgrid terms are closed with an eddy-viscosity or eddy-diffusivity approach, with an exception of the dominant subgrid term, which is the subgrid part of the chemical source term. The latter subgrid contribution is modeled by a similarity model based upon ¿, which is found to be superior to such a model based upon ¿. Using the 2¿ similarity model for the subgrid chemistry the LES produces good results, certainly in view of the fact that the LES is completely wrong if the subgrid chemistry model is omitted. The grid refinements of the LES show that the results for ¿ = h do depend on the numerical scheme, much more than for h = ¿/2 and h = ¿/4. Nevertheless, modeling errors and discretization error may partially cancel each other; occasionally the ¿ = h results were more accurate than the h = ¿ results.
AB - The accuracy of large-eddy simulation (LES) of a turbulent premixed Bunsen flame is investigated in this paper. To distinguish between discretization and modeling errors, multiple large-eddy simulations, using different grid size h but the same filterwidth ¿, are compared with the direct numerical simulation (DNS). In addition, large-eddy simulations using multiple ¿ but the same ratio ¿/h are compared. The chemistry in the LES and DNS is parametrized with the standard steady premixed flamelet for stochiometric methane-air combustion. The subgrid terms are closed with an eddy-viscosity or eddy-diffusivity approach, with an exception of the dominant subgrid term, which is the subgrid part of the chemical source term. The latter subgrid contribution is modeled by a similarity model based upon ¿, which is found to be superior to such a model based upon ¿. Using the 2¿ similarity model for the subgrid chemistry the LES produces good results, certainly in view of the fact that the LES is completely wrong if the subgrid chemistry model is omitted. The grid refinements of the LES show that the results for ¿ = h do depend on the numerical scheme, much more than for h = ¿/2 and h = ¿/4. Nevertheless, modeling errors and discretization error may partially cancel each other; occasionally the ¿ = h results were more accurate than the h = ¿ results.
U2 - 10.1007/978-1-4020-8578-9_25
DO - 10.1007/978-1-4020-8578-9_25
M3 - Conference contribution
SN - 978-1-4020-8577-2
T3 - Ercoftac Series (ERCO)
SP - 307
EP - 318
BT - Quality and reliability of large-Eddy simulations
A2 - Meyers, J.
A2 - Geurts, B.J.
A2 - Sagaut, P.
PB - Springer
CY - Dordrecht
T2 - conference; QLES Meeting / Workshop on Quality and Reliability of Large-Eddy Simulation ; 1 (Leuven) : 2007.10.22-24; 2007-10-22; 2007-10-24
Y2 - 22 October 2007 through 24 October 2007
ER -