Hi Stan, I think this type of boundary condition may only currently be working for scalar field. I did start a branch ( probably more than a year ago) which also mapped the velocity field when using an iterative solver. The issue is that we need to iteratively solver the velocity fields together so we can then apply the vector rotation rather than solving the velocity fields as a series of scalar problems which is what we do currently. If you wish I can try and find the branch and let you know? Cheers, Spencer. On 4 Nov 2021, at 21:50, Stanislaw Gepner <stanislaw.gepner@pw.edu.pl<mailto:stanislaw.gepner@pw.edu.pl>> wrote: This email from stanislaw.gepner@pw.edu.pl<mailto:stanislaw.gepner@pw.edu.pl> originates from outside Imperial. Do not click on links and attachments unless you recognise the sender. If you trust the sender, add them to your safe senders list<https://spam.ic.ac.uk/SpamConsole/Senders.aspx> to disable email stamping for this address. Hi, I am looking at the periodic BC with a rotation in a 2D flow. I managed to get NekMesh to work and align a PI-rotational boundary pair. I included a Rotated tag in the BOUNDARYCONDITIONS (it seems the tag is not used in 2D anyway), but what I get is not what I have expected. Consider attached figure, I have an outflow on top-right, rotated to bottom-right and I was expecting to see an inflow there. I had a look at the DisConstField.ccp, and there is a small piece of code setting everything up (~4,5k lines of code), and from what I understand rotation is not accounted for in a 2D case. My question is than: 1. Am I looking at the periodic-rotation BC in a wrong way? 2. Where are periodic BC enforced? I was unable to find the spot where I could just plug a *-1 to reverse the flow. Cheers, Stan -- Pozdrawiam, dr inż. Stanisław Gepner, Wydział Mechaniczny Energetyki i Lotnictwa Nowowiejska 21/25 Str. 00-665 Warszawa, Polska tel. +48 (22) 234 51 70 <6BwuTwNjpq2SByoU.png><http://www.pw.edu.pl/> <Screenshot from 2021-11-04 22-28-50.png>_______________________________________________ Nektar-users mailing list Nektar-users@imperial.ac.uk<mailto:Nektar-users@imperial.ac.uk> https://mailman.ic.ac.uk/mailman/listinfo/nektar-users