Hi Mahdi, Are you sure the problem should not be 2D? I see you are using a Reynolds number of 200 which is just above the onset of three-dimensionality for a stationary cylinder. I do not recall but the movement of the cylinder might delay the wake transition to 3D. Does you case become 3D if you do not move the cylinder since this might imply under resolution? Cheers, Spencer. Spencer Sherwin FREng, FRAeS Head of Aerodynamics Section, Director of Research Computing Service, Professor of Computational Fluid Mechanics, Department of Aeronautics, South Kensington Campus, Imperial College London, SW7 2AZ, UK Phone: +44 (0)20 7594 5052 http://www.imperial.ac.uk/people/s.sherwin/ On 28 Sep 2020, at 03:01, Mahdi Erfanian Nakhchi <mahdi.nakhchi@northumbria.ac.uk<mailto:mahdi.nakhchi@northumbria.ac.uk>> wrote: This email from mahdi.nakhchi@northumbria.ac.uk<mailto:mahdi.nakhchi@northumbria.ac.uk> 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 found an issue in moving cylinder problem in NEKTAR tests. I want to perform quasi 3D simulations over an oscillating cylinder by using mapping function. However, the velocity in the span direction (w) disappears after around 20,000 time-steps. In fact, the problem becomes full-2D after some time steps! I've tested various initial conditions for w, such as awgn(1) or awgn(1)*cos(2*PI*z/LZ), etc., and different mapping types, but I could not resolve it. I would be grateful if you could help me how to resolve this issue. The xml file and a screenshot are attached. Best regards, Mahdi This message is intended solely for the addressee and may contain confidential and/or legally privileged information. Any use, disclosure or reproduction without the sender’s explicit consent is unauthorised and may be unlawful. If you have received this message in error, please notify Northumbria University immediately and permanently delete it. Any views or opinions expressed in this message are solely those of the author and do not necessarily represent those of the University. Northumbria University email is provided by Microsoft Office365 and is hosted within the EEA, although some information may be replicated globally for backup purposes. The University cannot guarantee that this message or any attachment is virus free or has not been intercepted and/or amended. <mapping.xml><Screenshot.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