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

On the C0Projection
by Jian Yu 28 Mar '17

28 Mar '17

Dear everyone, I am trying to figure out the specific formulation when performing C0Projection, i.e. If I define m_c0ProjectExp as following m_c0ProjectExp = MemoryManager<MultiRegions::ContField2D>:: AllocateSharedPtr(m_session,m_graph,"DefaultVar"); Then what is the specific algorithm when perform the following command(all relative options are default)? m_c0ProjectExp->FwdTrans(var,var_Coeffs); m_c0ProjectExp->BwdTrans(var_Coeffs,var_smooth); If I have a discontinuous(across element interface) distribution of var, then what has been done during the above procedure? Could anyone please recommend me some materials on this? If possible, where can I find this topic on the book "Spectral/hp Element Methods for Computational Fluid Dynamics" Thank you in advance! Best wishes, Jian Yu

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Gitlab update
by David Moxey 26 Mar '17

26 Mar '17

Hi all, Just a quick note that I have taken the opportunity to update Gitlab this afternoon, as we were a few versions and security fixes behind. There are no major changes as far as we are concerned (asides from some minor interface tweaks), but if you encounter any issues then please let me know. Thanks, Dave

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Vcopy of complex numbers
by Kurt Sansom 23 Mar '17

23 Mar '17

I am trying to implement Vcopy for complex data type. What I started with was adding this line to Vmath.cpp in the template section. line 1082 template LIB_UTILITIES_EXPORT void Vcopy( int n, const std::complex<Nektar::NekDouble> *x, const int incx, std::complex<Nektar::NekDouble> *y, const int incy); but that seems to be insufficient because it compiles but gives the following error: dyld: Symbol not found: __ZN5Vmath5VcopyINSt3__17complexIdEEEEviPKT_iPS4_i I started looking at how the coefficients are handled in the FFT section, but It wasn't directly clear what the best approach to copying an array of complex numbers would be? Regards, ~Kurt -- Kurt Sansom Research Assistant Cardiovascular and Multiphase Flow Lab University of Washington

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Using nektar for stability analysis of a SteadyState base flow solution from commercial CFD tool(Fluent)
by devabratasahoo＠campus.technion.ac.il 21 Mar '17

21 Mar '17

Hi All, Is it possible to use Nektar for stability analysis of a base flow solution obtained from the commercial CFD tool (FLUENT)? Regards, Dev

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Stability analysis oSteadystate base flow solution from commercial tools
by devabratasahoo＠campus.technion.ac.il 20 Mar '17

20 Mar '17

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Nektar++ Workshop - 14th-16th June 2017
by Chris Cantwell 18 Mar '17

18 Mar '17

Dear all, We are pleased to announce that the Nektar++ Workshop for 2017 will take place on the 14th-16th June at Imperial College London, UK. Further details and information on how to register is available at: http://www.nektar.info/community/workshops/nektar-workshop-2017/ Please do get in touch if you have any questions or would be interested in presenting your current work relating to Nektar++. We hope to see you in June! Chris, David, Mike and Spencer

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Shock Capturing
by Song Ke 16 Mar '17

16 Mar '17

Hi Mellibovsky: Here is a case of transonic airfoil. I think it may be helpful to your problem. Cheers

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Shock Capturing
by F Mellibovsky 14 Mar '17

14 Mar '17

Hi all, I am interested in running the compressible flow solver (in principle just inviscid Euler) at supersonic Mach number on a sharp-leading-edge airfoil (attached shock expected). The solver seems to run just fine, but when I try to activate the shock-capturing option, the execution fails. I tried to find among the tests and examples the transonic airfoil case shown in the user-guide but I couldn't find it, plus the guide is not very clear on how to use shock-capturing. Can someone share a conditions file that has shock-capturing activated with the compressible Euler solver? Thanks in advance for any help with this. Cheers

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Nektar++ v4.4.0 Released
by Chris Cantwell 09 Mar '17

09 Mar '17

Dear all, We are pleased to announce the next release of Nektar++, v4.4.0. This release includes a wide range of new features including: - a new FieldUtils library which makes much of the FieldConvert functionality available to solvers on-the-fly, - support for HDF5 as an output format, - support for variable polynomial order in 3D CG discretisations, as well as many other improvements and bug fixes. Many of the solvers and utilities have also received major improvements. A full list of the changes is available in the CHANGELOG.md file distributed with the source code. As always, if you encounter any problems please feel free to contact us on the mailing list nektar-users(a)imperial.ac.uk. Cheers, Chris -- Chris Cantwell Imperial College London South Kensington Campus London SW7 2AZ Email: c.cantwell(a)imperial.ac.uk www.imperial.ac.uk/people/c.cantwell

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extracting isosurfaces on runtime
by Asım Önder 08 Mar '17

08 Mar '17

Dear all, Is there any way to make isocontour module work in filter mode for derived quantities, e.g., Q field? I tried the following in config.xml file for a run using IncNavierStokesSolver solver: <FILTER TYPE="FieldConvert"> <PARAM NAME="OutputFile">Q_214.fld</PARAM> <PARAM NAME="OutputFrequency">10</PARAM> <PARAM NAME="Modules"> QCriterion </PARAM> </FILTER> <FILTER TYPE="FieldConvert"> <PARAM NAME="OutputFile">Q_214_iso2000.fld</PARAM> <PARAM NAME="OutputFrequency">10</PARAM> <PARAM NAME="Modules"> isocontour </PARAM> <PARAM NAME="fieldstr"> Q </PARAM> <PARAM NAME="fieldvalue"> 1000 </PARAM> </FILTER> The first filter works, and writes out the 3D Q field. However, second one does not work as Q is not defined as a field in the solver. Is there any possibility to address this other than extending the related solver to contain the calculation of the field? Thanks, Asim

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