[acalado]

Hi gents,

so I'm trying to run a simulation where I have a transient fire inside a tunnel section.

I am using energy and mass sources to model the fire, and zero pressure BC at the outlets. The fire is supposed to take a few minutes to ramp up so this is a quite large simulation (both due to the size of mesh and physical time span)

I am using pressure-based solver with SIMPLE, tried using 1st order schemes and under-relaxations down to 0.5 but still am having trouble converging.

I tried using adaptive time steps but still no luck. Should I just use a very small time step (i.e. 1e-4 ?)in the beginning, and then increase this?

Thanks for your help!