LES problems
 

Hi all,

Currently, i using ECFM with LES simulate the combustion in spark ignition gasoline reciprocating engine. However, there are no combustion occurs when i look at the flame surface density result. I also tired to input knocking effect during the combustion, but the propagation of flame is weird.
With the same configuration but different equation like K-Epsilon, K-Zeta-F and Pans, the results were just okay. I also noticed that when i used LES to run the simulation, the simulation completed far more quicker than K-Epsilon, K-Zeta-F or Pans. Supposingly, LES should take a longer period to run right? I am confused.
I was wondering anyone also encounter this kind of problem. I am so new with AVL, so please kindly guide me.

Regards,
Roy