March 2022 - Nektar-users - imperial.ac.uk

Meshing of random packed spheres
by Daniel Lester 03 Apr '22

03 Apr '22

Hi Nektar Users, I’m not a Nektar user but I am considering using this code for a project involving computation of flows across the interface of a porous medium comprised of random packed spheres (RPS) - i.e. flow within the medium, the boundary layer and the turbulent bulk. Previous finite volume models of RPS involved smoothing of the cusp-shaped geometry at the contact points between spheres. Would this geometry be feasible to mesh and run in nektar if the # of spheres was order 100's, or would this be getting too fiddly/complex? Any feedback greatly appreciated, cheers Daniel

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Q3D simulations around cylinders
by Alessandro Alberto de Lima 26 Mar '22

26 Mar '22

******************* 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. ******************* Hi. How are you? I am running some cases of flow around cylinders and, for the case of Re = 1000, I get curious results. The lift force history showed strange oscillations like presented in the attached images. I am using SVV with 64 Fourier modes in z direction for the simulations and my mesh was developed following the descriptions found in a recent publication involving nektar++ and OpenFOAM. I believe that the mesh is not the problem. There is another option for pressure solution and force calculations? Have you any idea about what I'm doing wrong? Thank you! Alessandro

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monitor the torsional force of a 2-D cylinder in the new version code nektar ++ 5.10
by hongfu2233 15 Mar '22

15 Mar '22

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Stability convergence criteria
by Matt Duran 15 Mar '22

15 Mar '22

******************* 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. ******************* Hello Nektar++ community, I recently have been running an adjoint stability simulation and am interested in the vortex shedding mode. >From the Strouhal number found in the literature I know the eigenmode of interest is the one highlighted below with a magnitude of 0.97 and a frequency of 0.731. [image: image.png][image: image.png] I have tried using a Krylov space of 40 and instructing Nektar to wait for the 20 modes with the highest magnitude to converge but I have no luck in getting the specific mode of interest to converge. I was wondering whether there was some way I could narrow down the convergence criteria so the specific mode I need will converge, rather than these other 20 modes I’m getting. I have tried to also converge modes by the highest imaginary part but I can’t seem to get the specific mode I need. Thank you, Matt Duran PhD student University of Central Florida

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Incompressible Navier-Stokes Solver
by Dongmyung Suh 03 Mar '22

03 Mar '22

******************* 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. ******************* Hi All, I am studying Nektar++ by following the tutorial of Incompressible Navier-Stokes Solver in ( https://www.nektar.info/notebooks//tutorials/basics-incns-solver/) I wrote the condition file (mysession.xml) following the direction in the website. But it didn't work. I guess that there were some info missing. When I checked session2d.xml <https://www.nektar.info/notebooks//tutorials/basics-incns-solver/session2d.…> , there was also some error. So I couldn't see the correct working file. How can I get the session file? Please let me know. Thanks, Dongmyung Suh

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