Hi Dustin, Thank you for your e-mail. Based on the evidence we have, this issue seems to be related (I might be wrong) to not applying the periodic alignment module of NekMesh. For periodic boundaries, the vertex IDs on the inlet and outlet have to "match" and this is achieved by running NekMesh -m peralign. Could you check if you have applied this module on your mesh? Cheers, Chi Hin ________________________________ From: nektar-users-bounces@imperial.ac.uk <nektar-users-bounces@imperial.ac.uk> on behalf of Ma, Ting-Hsuan <TIM48@pitt.edu> Sent: 04 April 2023 14:40 To: nektar-users <nektar-users@imperial.ac.uk> Subject: [Nektar-users] Mesh Generation and Simulation Error This email from TIM48@pitt.edu 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'm currently working on a project involving the periodic hill geometry, and I've encountered an issue with the mesh simulation using Nektar. Despite successfully creating a decent mesh and correctly labeling all physical groups (inlet, outlet, top, and bottom boundary), I've noticed that the vertices at the inlet seem to exhibit a no-slip boundary condition, while the edges themselves seem to follow a periodic inlet/outlet condition. This behavior is unexpected since I've specified a periodic inlet/outlet boundary condition during the simulation. Has anyone experienced this problem before and found a way to resolve it? Any suggestions or insights would be greatly appreciated! A figure of P order of 5 is attached to demonstrate the problem visually. [cid:image001.png@01D966D9.475EC5B0] Thanks, Dustin Ma