So, here is my situation: I am trying to introduce noise into my initial conditions for a Turbulent Channel DNS using awgn(). Currently, it is set up along the lines of u = 1.0 + 0.1*awgn(1.0). However, for what we are doing, we need this initial noise to be symmetric over the XY-plane at the middle of the channel (i.e. the bottom half is identical to the top half). I have been trying various combinations of modules in FieldConvert, but I feel as though I'm missing something. (If you could offer and insight on this, that would be great.) My other idea was to bring the initial field into a program such as paraview, and then make the necessary edits there. However, after reading and tinkering, I don't believe that FieldConvert has the ability to read in a VTK file and convert it back to a FLD file. Is there any way to actually read in data from a source such as VTK file or some other non-Nektar++ source? I tried this with a tecplot file, but it does not seem to want to read it.
Hi Marcus, Sorry for the slow response! We don't right now have the ability to import directly from VTK. However, FieldConvert does have the ability to interpolate pointwise data onto a Nektar++ mesh and dump out a field file. This is described in the user manual (see the section on interppointdatatofld in the FieldConvert chapter). You need to make a simple .pts file as described in this section. Be aware that this might very well introduce small non-symmetric interpolation errors, so bear this in mind in the context of the DNS simulations. It may therefore be necessary for us to investigate other options such as a specifically designed bit of code to introduce the necessarily perturbation. Cheers, Dave On Thu, 2016-07-07 at 23:57 +0000, Lander, Marcus David wrote:
So, here is my situation: I am trying to introduce noise into my initial conditions for a Turbulent Channel DNS using awgn(). Currently, it is set up along the lines of u = 1.0 + 0.1*awgn(1.0). However, for what we are doing, we need this initial noise to be symmetric over the XY-plane at the middle of the channel (i.e. the bottom half is identical to the top half). I have been trying various combinations of modules in FieldConvert, but I feel as though I’m missing something. (If you could offer and insight on this, that would be great.) My other idea was to bring the initial field into a program such as paraview, and then make the necessary edits there. However, after reading and tinkering, I don’t believe that FieldConvert has the ability to read in a VTK file and convert it back to a FLD file. Is there any way to actually read in data from a source such as VTK file or some other non-Nektar++ source? I tried this with a tecplot file, but it does not seem to want to read it. _______________________________________________ Nektar-users mailing list Nektar-users@imperial.ac.uk https://mailman.ic.ac.uk/mailman/listinfo/nektar-users -- David Moxey (Research and Teaching Fellow) d.moxey@imperial.ac.uk | www.imperial.ac.uk/people/d.moxey
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participants (2)
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David Moxey
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Lander, Marcus David