Hi,

i've set a mesh which converged,but when refining the convergence was achieved ,is the problem a timescale kind or acually a mesh one.

thanks

Dear amine, it is hard to understand what whould you like to know.

both cases converged, so what is the problem?

matej

Hi,

my question was, i set a mesh that converged,when refining that mesh the solution didn't converge at least after a large timestep iterations & ocilated which wasn't the case previously.

thanks

You are probably resolving details in the flow the prior mesh could not and these disturbances are affecting convergence.

Hi,

Craig is correct. Try using a larger physical timescale.

Glenn Horrocks

I don't see the logic behind increasing timescale whenever you see oscillation. What if that oscillation is a real physical phenomenon? Using large timescale to get rid of oscillation just for sake of getting converged result is not always a good practice.

Hi,

I agree with you longbow. The full answer is work through the points on this link, of which increasing timescale is one:

http://www.cfd-online.com/Wiki/Ansys...gence_criteria

ps: I wrote this FAQ answer so I am well aware that there is more to it than just increasing the timestep!

But I am a lazy typer so couldn't be bothered writing the whole thing every time somebody asks it. This question has been asked dozens of times so it gets pretty boring.

Glenn Horrocks