Hi Syavash, Could you send the command you used? Also note that to modify the bl, the mesh should have a closed bl with only one layer of mesh. So if using other software to mesh, set it to produce only a single layer that spans from wall to an extent you wish Cheers Mohsen Mohsen Lahooti Lecturer in Fluid-Structure Interaction Mechanical Engineering Newcastle University School of Engineering Stephenson Building Newcastle upon Tyne NE1 7RU UK ________________________________ From: nektar-users-bounces@imperial.ac.uk <nektar-users-bounces@imperial.ac.uk> on behalf of Ehsan Asgari <eh.asgari@gmail.com> Sent: Tuesday, April 25, 2023 11:36:36 AM To: nektar-users@imperial.ac.uk <nektar-users@imperial.ac.uk> Subject: [Nektar-users] wrong number of modes ⚠ External sender. Take care when opening links or attachments. Do not provide your login details. This email from eh.asgari@gmail.com 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. Dear All, After I converted the mesh to xml format with order=7 (using NekMesh), I tried to split the first layer adjacent to a wall using the "bl" module with nq=7. However, I get the following error: Wrong number of modes? Is there an incompatibility issue here? Kind regards syavash