OpenLB 3D cylinder example

[simonguo]

Hi all,rnrnI am a new learner for OpenLB. rnI was running 3D cylinder example as a test. After I open *.vti file, I see the geometry seems like a cubic, but the exported cylinder3d.stl file (the computational domain) is a rectangular domain.rnrnCould anyone tell me why the geometry in vti file and stl file different?rnrnBTW, I am very stuck in using Paraview, as I was used to apply tecplot as the post-processing s/w. How to see the streamlines or contours in different planes for the 3D cases?rnrnThank you so much for your answers.rnrnSimon

[quadrupole]

I kind of have the same problem – it seems that the .vti files contain several parts of the geometry in question.rnrnAs for paraview, you can easily visualize streamlines by using the “”Streamtracer”” filter. In paraview you apply filters to your data pipeline and that will modify your data, so that the next filter can operate on that as well. For visualising planes you have the “”Slice”” filter. Apply a slice and then the “”Generate Surface vectors”” filter. You can select ‘parallel’ as a option and this will project your vectors onto that plane. Then I would use the “”Glyph”” filter with the velocity field as input to visualise the streamlines. You can do this wit the stream tracer too. Honestly paraview is great, you can create some customizable filters if what exists is not what you want. rnrnHave a look here to get started with what you need: http://www.aerodynamic-solutions.com/help/knowledge-base/help/kb/article/creating-surface-vectors-with-paraviewrnrn

[simonguo]

Hi quadrupole,rnrnThank you for your introduction on ParaView, as well as the useful website. Let us wait for others help on that .vti issue.

[robin.trunk]

Hi simonguornrnthe vti just contain a part of the geometry. This informations are assembled in the .pvd files. Just have a look at my today’s post in this topic:rnhttp://optilb.org/openlb/forum?mingleforumaction=viewtopic&t=159rnrnBestrnRobin

[simonguo]

Quote:

Quote from robin.trunk on August 23, 2016, 08:42rnHi simonguornrnthe vti just contain a part of the geometry. This informations are assembled in the .pvd files. Just have a look at my today’s post in this topic:rnhttp://optilb.org/openlb/forum?mingleforumaction=viewtopic&t=159rnrnBestrnRobin

rnrnrnHi Robin,rnrnThank you for the help. It’s quite useful for me. rnrnI noticed your answer in another topic “”For Each timestep in the same folder there is a file “”cylinder2d_iTxxxxx.pvd”” that shows the solution for the whole geometry in the specific timestep.rnIf you want to open all the data in Paraview so that you can press play, just open the file “”cylinder2d.pvd”” in the folder “”vtkData””.””rnrnI tried to open cylinder3d_iTxxxxx.pvd in Paraview 5.0.0, but it was still failed, nor did “”cylinder3d.pvd””. What’s the reason for that? (The code is still running, but I think it is not affect the existing files.)rnrnThanks again.rnrnSimon

[robin.trunk]

Hi Simon,rnrnit should work, I tried with the same Paraview version. Maybe doing a “”make clean”” to delete old files before executing helps.rnDoes some error show up?rnDid you change something in the code?rnrnBestrnRobin

[simonguo]

Hi all,rnrnMy problem has been worked out. As the cylinder3d_iTxxxxx.pvd is linked with the .vti files for the same time step, cylinder3d_iTxxxxx.pvd file couldn’t open seperately. So if I want to open it in another machine, I need to cope all related file together (including seven .vti files, and .pvd file for the same time step). rn

[simonguo]

Quote:

Quote from robin.trunk on August 25, 2016, 07:30rnHi Simon,rnrnit should work, I tried with the same Paraview version. Maybe doing a “”make clean”” to delete old files before executing helps.rnDoes some error show up?rnDid you change something in the code?rnrnBestrnRobin

rnrnHi Robin,rnrnAnother question may need your kind help.rnIf I want to modify the geometry for cylinder3d (like shorten the cylinder length, but keep the original domain, so that cylinder doenn’t penetrate the domain), what should I do?rnrnI referred to “”http://optilb.org/openlb/forum?mingleforumaction=viewtopic&t=38″”, and have 2 ideas: rn1) edit the cylinder3d.stl file in freecad. I just wonder which file I need to modify? *.stl or *.fcstd? Besides the geometry, is there any mesh generation issues regarding to build my own geometry?rnrn2) Dr. Mathias mentioned “”/ set the material numbers “”by hand””rn””blockGeometry.setMaterial(iX, iY, iZ, 2);”” But I failed to find that block. Is this block still in cylinder3d.cpp?rnrnThanks for your kind advice.rnrnSimon

[robin.trunk]

Hi Simon,rnrnI think there are 3 options to do this:rnrn1) Edit the .stl file like you said. Here you just need to modify the STL, not the fcstd. However the material number for the cylinder is set in “”prepareGeometry””, you maybe have to adapt the “”/// Set material number for cylinder”” part.rnrn2) You can construct your own geometry using the indicator-functors. This way you can easily modify your geometry later on, just like in cylinder2D.rnrn3) You can set material numbers by hand. You can’t find a blockGeometry, since a superGeometry is used, that consists of blockGeometries. Looking at the doxygen the superGeometry3D has functions “”set”” to modify the material number. However I think this would be the most work intensive way to modify the geometry in your case.rnrnBestrnRobin

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