Learning Forum

[sharm2a2]

I am running unsteady flow in a pipe and and I am not getting periodic behavior in residual. The residuals  are just decreasing as if it's a steady flow. 

Can anyone explain why?

 

Thanks 

[DrAmine]

You can imagine that an unsteady analysis is a set of steady state runs. So every transient will be started by the result of the steady state result coressponding to previous time step. If the initialization is so good snd/or the taylor extrapolation is doing right then the periodic pattern won't appear. Check the behavior of monitor points within a time step along the number of iterations. Uncheck at first convergence by residuals for understanding a transient loop with at least 3 inner coefficents liniarization is important 

[sharm2a2]

Hi Abenhadj

Thank you very much