March 2017 - Nek5000-users - mailman3.cels.anl.gov

how to dumping velocity data in each processor to file
by nek5000-users＠lists.mcs.anl.gov 09 Mar '17

09 Mar '17

hi, all I'm trying to write down velocity in each processor into files. Below is an sample in the subroutine userchk: open(unit=80,file='result.dat') write(80,*) 'x, y, z, u, v, z, p' do e=1,nelv do k=1,lz1 do j=1,ly1 do i=1,lx1 write(80,1) xm1(i,j,k,e),ym1(i,j,k,e),zm1(i,j,k,e), & vx(i,j,k,e),vy(i,j,k,e),vz(i,j,k,e),pr(i,j,k,e) enddo enddo enddo enddo 1 format(1p15e17.9) But in this case ,I can get the data only in one processor. When I use more than one processor, how to get velocity in all processors? Best regards! Hu

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VISIT visnek skip some timesteps
by nek5000-users＠lists.mcs.anl.gov 07 Mar '17

07 Mar '17

Dear Neks, I generate blah0.00001, blah0.00002, .....blah0.f00101 on a remote computer. But, I transfer only blah0.f0*1 because of slow transfer speeds. When I run visit, it throw error from the second frame (timestep) Can someone kindly let me know how should the blah.nek5000 file be modified in order to visualize in VISIT? When I transfer all the files there is no problem in running VISIT. Thank you in advance.

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Problem with Spatial Derivatives of field
by nek5000-users＠lists.mcs.anl.gov 06 Mar '17

06 Mar '17

Hi Neks, I'm having some problems with computing the gradients of vorticity. So what I do in the usercheck is something like : call call comp_vort3(vort,work1,work2,vxp,vyp,vzp) ! Computing vorticity of perturbations call gradm1(derivvortx,derivvorty,derivvortz,vort(1,1)) However, by doing this I do observe some abnormal results when I plot the fields : derivvortx, derivvorty, derivvortz. Attached you will find a snapshot of the magnitude of derivvortx and derivvorty (obtained using paraview) I am wondering why I am having extremely high values a the boudary of the elements. Has anyone noticed or faced such a problem? Even when I increase lx1, reduce dt and reduce the mesh size, the problem remains.. Thank you for your time, Best wishes, Arnold -- *Arnold Wakim* Doctorant, Département d´Aérodynamique Fondamentale et Expérimentale Tél: +33 1 46 23 51 83 ONERA - The French Aerospace Lab -Centre de Meudon 8, rue des Vertugadins - 92190 MEUDON Nous suivre sur : www.onera.fr <http://www.onera.fr/> | Twitter <http://www.twitter.com/@onera_fr> | LinkedIn <http://www.linkedin.com/company/onera> | Facebook <http://www.facebook.fr/thefrenchaerospacelab>

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Azimutal velocity on axisymmetric simulation
by nek5000-users＠lists.mcs.anl.gov 03 Mar '17

03 Mar '17

Hi all, I have been running an axisymmetric case for some time now tricking the temperature array into storing azimutal velocity data (IFHEAT T, IFAZIV T). Right now, I have an initial condition on "temperature" of 1.0E-12 so that it is not zero and the results I have been getting are not consistent in a way where I can run the same case (same ".rea", same ".usr", same "SIZE") and get two very different results for the "temperature" field: either it diverges very quickly (around 30th time step) and shows "Inf" or it stays at around 1.0E-12 with some minor perturbations for the rest of the simulation. Just to be clear, simply stopping the simulation and re-running it from t=0 will "switch" between those two results. Any advice will be appreciated, MViturro

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