[Nek5000-users] Local Refinement

[nek5000-users at lists.mcs.anl.gov]

Hi All,
I have simulated an eccentric stenosis problem at Re=1000 to verify against Varghese et al., JFM 2007 but my RMS and TKE plots are relatively damped compared to their study. The mesh used in their study appears to show local refinement near the jet breakdown region, which would indicated non-conforming elements. On the other hand, I have no local refinement where the jet breakdown occurs, which probably explains the discrepancy.

Without local refinement, my mesh size would be on the order of ~20M grid points, compared to 5M grid points used by Varghese et al. to achieve DNS. I have searched the documentations but couldn’t find a clear answer on this. I have two questions and I would greatly appreciate if someone could answer them, or point me in the correct direction:

1) Is local refinement already implemented in the current version of NEK5000? If yes, is there any documentation available to which I can refer?
2) If local refinement is implemented, what is the best method to refine my mesh? Can I somehow loop over the elements and tag the ones I want to refine in .usr file? Or is there a graphical interface to do so?

Thank you very much in advance and any help is greatly appreciated :) 

Regards,
Owais Khan