[Joeyt]

Hello!
I am trying to run a 3D in-cylinder spark ignited combustion model of of an engine. I can run the model perfectly through a cycle with cold air, but when I introduce combustion with a premixed fuel model the solution diverges just a few time steps after spark ignition. I tried playing around with the underrelaxation factors, but it is still diverging at the same point. are there any tricks to addressing this type of situation that someone has dealt with before?

Thanks!