<html><body><div style="font-family: arial, helvetica, sans-serif; font-size: 12pt; color: #000000"><div>Hi Neks,<br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div><div>I did a mesh conversion from ICEM to NEK with ' ' (3 spaces) as boundary conditions instead of periodic. (It is a 3D naca profile). I tried n2to3 method for extrusion but I am not confident with that method since I already have a 3D mesh and my future works will be like that.<br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div><div>So my problem is, I am trying to set periodic boundary conditions on both sides of the naca wing. I use prex for that.<br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div><div>When I use prex for simple gemetries like cube and cylinder, the periodic conditions are set well.</div><div><br data-mce-bogus="1"></div><div>But when I try on NACA the periodic BCs become in consistent and it runs a loop to check the consistency and not generating rea file anymore.</div><div><br data-mce-bogus="1"></div><div>I commented some lines in source code (tools/prenek/bound.f) and tried to figure whats going on, then I generated an rea file and checked inside.<br></div><div><br data-mce-bogus="1"></div><div>I saw that some elements are not set with Periodic bcs. </div><div><br data-mce-bogus="1"></div><div>I understand that the loop helps to make the BC consitent.<br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div><div>But could you please tell me why it happens to NACA and not for simple gemoteries.</div><div><br data-mce-bogus="1"></div><div>I am really stuck here..<br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div><div>Thank you<br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div><div>Sijo GEORGE<br data-mce-bogus="1"></div><div> <br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div></div></body></html>