[acalado]

Greetings,

I have a transient simulation where for the first period some boundaries are walls, and after that I change them to velocity boundaries with a ramp up increase in the velocity using UDFs.

The ramp up should take the value at the end of the first period and then linearly ramp up with time, however I am having some issues on convergence.

I have tried using small timesteps and lower under-relaxation factors but still with trouble.

Any suggestions are appreciated!

Thanks