May 2017 - Nektar-users - imperial.ac.uk

Nektar++ transition to C++11
by Chris Cantwell 09 Sep '17

09 Sep '17

Dear all, As part of our ongoing efforts to modernise our codebase, we are planning to transition to the C++11 standard in the near future. A consequence of this is that you will in future require a compiler which supports the C++11 standard (either as an option, such as --std=c++11, or by default). Current versions of popular compilers all fully support the standard, but older compilers may only have partial support. We recommend the following compiler versions to minimise the likelihood of problems going forward: - GCC: 4.8 or later - Clang: 3.3 or later - MSVC: 19.0 or later - Intel: 15.0 or later - PGI: 2015 or later We encourage users to test out support for basic C++11 by compiling the branch 'feature/libutils-c++11' from the code repository and updating build scripts and configuration as necessary. Please let us know if you have any problems or concerns. We will be making the transition after the Nektar++ Workshop in mid-June. Cheers, Nektar++ Development Team

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Floquet analaysis
by F Mellibovsky 04 Jun '17

04 Jun '17

Dear all, I have computed a stable *2D periodic solution* with nektar++ time evolving the *incompressible Navier-Stokes solver*. Now I would like to analyse it's *stability to spanwise-dependent perturbations*. I have started doing this with time evolution, by using a homogeneous spanwise direction with just one mode and monitoring its growth rate. This is however extremely slow. I have noticed that in the user guide there's an example that does Floquet stability analysis on the periodic 2D vortex shedding solution of the flow around a cylinder, but unfortunately I haven't manage to find the conditions xml file used for the computations. Does anyone have it, so that I can use it to set up my *Floquet analysis*? I have doubts as to how a sequence of snapshots along a period are loaded and also about the differences between using Arpack or modified Arnoldi, among other issues. I would be very greatful if someone can send me an conditions file exemplifying the implementation of Floquet analysis. Many thanks in advance. Cheers, Fernando Mellibovsky

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Re: [Nektar-users] NEKTAR ++
by Sherwin, Spencer J 08 May '17

08 May '17

Dear Hamed, Thanks for your interest in our software. I am not a user of visual studio but am cc’ing one of the researchers, Julian, who does use Nektar++ in this environment. Perhaps you could clarify what problems you are having and we can see if Julian can help. Regards, Spencer. On 1 May 2017, at 20:16, Hamed Faghanpour Ganji <h.f.ganji(a)gmail.com<mailto:h.f.ganji@gmail.com>> wrote: Dear Dr. Sherwin, Greeting! My name is Hamed Ganji and I am a young researcher in Acoustic fluid solid interaction, I see your invaluable publications and also your developed software (Nektar++) is found very interesting for my major goal in current project, really I would like to use it in my future works, but my familiar with this software and Visual studio and other related package according to NEKTAR ++ help in pages 9-16, so I could not use this one till at present, May you please help me with your guidance that how can use this useful open source codes. With Best Regards, Hamed Ganji Spencer Sherwin McLaren Racing/Royal Academy of Engineering Research Chair, Professor of Computational Fluid Mechanics, Department of Aeronautics, Imperial College London South Kensington Campus London SW7 2AZ s.sherwin(a)imperial.ac.uk<mailto:s.sherwin@imperial.ac.uk> +44 (0) 20 759 45052

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Re: [Nektar-users] probing variables over 2D mesh
by Sherwin, Spencer J 07 May '17

07 May '17

Dear Ronald, Very sorry for a slow response. I have not been keeping onto of emails this past week. I am forwarding your request to the nektar-users list to see if anyone else has an answer. We do not have a specific function for this currently unless someone else has implemented it. We do have some features in FieldConvert to extract a box or plane of points. Whilst these methods are now callable from the solvers this would be very costly since it would search out for the points in the mesh at every call and to make this more efficient you should ideally only be searching for the points to extract once and then only interpolate every time you wish to extract this information. This is currently how the history points filter works. Cheers, Spencer. On 29 Apr 2017, at 10:06, ronald russ <rnld_russ(a)yahoo.com<mailto:rnld_russ@yahoo.com>> wrote: Hello, I am currently doing 3D ADR simulations on a 3D domain. What I really need is to probe the variables, but not on specific point(s), on a 2D mesh of a unit sphere which is contained in the 3D domain. This means probing on nodes of the triangular grid of the sphere which is in 2D. Please could you let me know if there is an straightforward way to probe fields on the nodes on this 2D mesh. Best, Ronald Spencer Sherwin McLaren Racing/Royal Academy of Engineering Research Chair, Professor of Computational Fluid Mechanics, Department of Aeronautics, Imperial College London South Kensington Campus London SW7 2AZ s.sherwin(a)imperial.ac.uk<mailto:s.sherwin@imperial.ac.uk> +44 (0) 20 759 45052

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