Questions about the plane of rotational periodic symmetry
******************* This email 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 Nektar++ users, I am attempting to use Nektar++'s rotational periodic boundary conditions. After generating the mesh, surfaces 5 and 6 in the .msh file can be joined together by rotating around the z-axis by Pi/6. However, when I use the command provided in the help documentation: NekMesh -m peralign:surf1=5:surf2=6:dir=z:rot=PI/6 test.xml test_align.xml the process always fails, displaying the following warning: [ProcessPerAlign] WARNING: Could not find matching edge for surface element 3. Skipping periodic alignment. I have been unable to resolve this issue on my own. If anyone could provide assistance, I would be extremely grateful. Attached to this email, you will find the corresponding .geo, .msh, and .xml files that I have been using for testing. Thank you very much for your help. Best regards, Yaguang
Hi Yaguang, Thank you for getting in touch. Unfortunately, I cannot open the files due to an email firewall, but I should be able to help. There are several possible reasons you might be experiencing this issue: 1. Surfaces/Composites - 5,6 need to be the matching same - number of faces, [x,y,z] of the vertices and centroids of the faces. - This is related to the way you generate your mesh and the periodicity usually needs to be specifically enforced. 2. Machine precision tolerances in some of the elements in the original : - Recommend adding abstol=tolValue NekMesh -m peralign:surf1=5:surf2=6:dir=z:rot=PI/6:abstol=1e-6 test.xml test_align.xml 3. Type of elements used - if you have prisms or tets in the mesh: - Need to add the orient flag NekMesh -m peralign:surf1=5:surf2=6:dir=z:rot=PI/6:abstol=1e-6:orient test.xml test_align.xml I think this should help. If it does not, could you please let us a bit more details about how you generated the mesh, type of elements, etc? Kind Regards, Kaloyan Kirilov ________________________________ From: nektar-users-bounces@imperial.ac.uk <nektar-users-bounces@imperial.ac.uk> on behalf of 谢亚广 <xieyaguang@iet.cn> Sent: Saturday, March 30, 2024 11:21 AM To: nektar-users <nektar-users@imperial.ac.uk> Subject: [Nektar-users] Questions about the plane of rotational periodic symmetry This email from xieyaguang@iet.cn 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 Nektar++ users, I am attempting to use Nektar++'s rotational periodic boundary conditions. After generating the mesh, surfaces 5 and 6 in the .msh file can be joined together by rotating around the z-axis by Pi/6. However, when I use the command provided in the help documentation: NekMesh -m peralign:surf1=5:surf2=6:dir=z:rot=PI/6 test.xml test_align.xml the process always fails, displaying the following warning: [ProcessPerAlign] WARNING: Could not find matching edge for surface element 3. Skipping periodic alignment. I have been unable to resolve this issue on my own. If anyone could provide assistance, I would be extremely grateful. Attached to this email, you will find the corresponding .geo, .msh, and .xml files that I have been using for testing. Thank you very much for your help. Best regards, Yaguang
participants (2)
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Kirilov, Kaloyan S
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谢亚广