Transient run taking too long time
 

Hi all.

My name is Alexander. I am running transient run for solid-liquid flow in a horizontal annulus.

I am facing a problem, which is my run is taking too long time. It sums up to 3 days and still running.

Previously, I have make changes in my setup as I read the related posts in this forum.

My current time step is of 0.001 s and my run is computed over a period of 100s. My model length is only 2 ft!!!

May I know what are the potential problems that I may have not identified in my setup?

Thank you very much.


Regards,
Alexander Tham
tham.keatfu@gmail.com

Have you considered using adaptive time-stepping?

In case if you choose to use that, make sure you select a reasonable residual target and convergence criteria. If you select too stringent and aggressive convergence target (i.e. small), adaptive time-stepping takes very small time-steps, and convergence takes like aeons.

Also, running local parallel may help in speeding things up.

Regards
OJ

Thanks, OJ.

I will try using adaptive time step and let you know how is the progress. In addition to that, may I know in a normal transient simulation, how long would it takes?

Thanks. Appreciate your feedback.

Regards,
Alex

How long it'd take may depend on several things, the models that determine the amount of equations solved, the timestep size, the convergence criteria, the mesh resolution... Did you do a mesh sensitivity analysis to check you're not using a mesh that is too fine for this purpose?