January 2014 - Nek5000-users - mailman3.cels.anl.gov

Creating a Mesh
by nek5000-users＠lists.mcs.anl.gov 13 Jan '14

13 Jan '14

Hi Can some one please help me in this because I am new to nek 1) How can I create a .rea for a specific geometry say ' A sudden expansion pipe ' or a ' Diverging pipe ' 2) What tool I should use to create that mesh. Thank you kamal

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Possible to read solution *.fld# or *.f# files in matlab ?
by nek5000-users＠lists.mcs.anl.gov 11 Jan '14

11 Jan '14

Hello Is it possible to read the nek solution files in matlab ? I want to do some postprocessing. If yes, are there any examples ? Thanks praveen

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The first time step in a Nek file must contain a mesh error
by nek5000-users＠lists.mcs.anl.gov 10 Jan '14

10 Jan '14

Hello, I am using VisIT for nek5000, I tried some of the tutorials from Nek5000. I was able to launch and create the metadata file for Eddy_uv example. I tried to do the same for the Helix Pipe example but when I loaded the metadata file into VisIT, I got an error saying " The first time step in a Nek file must contain a mesh " This is my metadata file for the pipe helix example --------------------------------------------------------------------- NEK5000 version: 1.0 helix.rea filetemplate: helix0.f%05d firsttimestep: 1 numtimesteps: 1 --------------------------------------------------------------------- Can some one tell me how to add mesh to the first time step. Thank you, Kamal

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fft in nek5000 or Visit ?
by nek5000-users＠lists.mcs.anl.gov 04 Jan '14

04 Jan '14

Dear Neks I have my turbulent flow in a 3D box for which I would like to perform a Fourier analysis in one direction (y) at several selected time steps in order to find the discretized spectral representation (up to resolution of say N=128 wave numbers) of streamwise vorticity (w_x). I have been trying to find the best way to approach this in nek by reading the user mailing list but am troubled to decide and would appreciate it if the experienced users could guide me: 1) Using int_tp tool (in repo, trunk/tool/) one can interpolate the nek SEM output results to uniform, SEM and non-uniform (selected points) but I guess this only works for small grids? At least I got seg fault for my larger grids. Alternatively, we can use "ifreguo = .true." in userchk via post-processing the data in parallel. And then use a separate fft library (eg. MATLAB) to read in the uniform grid and do fft. But there will be memory issues for larger datasets. How can I resolve this? 2) I noticed that Visit has an FFT operator (at least in my v 2.6.3) for which I could not find any documentation. Does anyone have any knowledge of how it works? 3) One could also do the fft by adding proper subroutines in .usr file and calling them in userchk. Does anyone here have the right set of subroutines for this purpose? Thank you, Hesam

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