Fluids

Fluids

What Are Good Orthogonal Quality Values?

    • Atgeirr
      Subscriber

      Hello there everyone,

      I'm having trouble understanding what ''good'' orthogonal quality values are. I'm aware that the absolute minimum orthogonal quality for Fluent is 0.01. However what is a good way of determining if my orthogonal quality is sufficient?

      I'm using Fluent with the K-w SST viscous model.

      My current mesh has the following Quality values:

    • Karthik R
      Administrator
      Hello,nRegarding minimum orthogonal quality, the best practice is to keep the minimum value above 0.1. If you visually inspect these cells with lower than the quality threshold, these cells are squished - which is not good for the Fluent solver. This is just a rule of thumb to obtain better-converged results.nKarthikn
    • Atgeirr
      Subscriber
      Thank you Kremella,nI do have a follow-up question if that is ok.nAs of right now I'm still only using the student version of Ansys, so I'm limited by the maximum amount of nodes Fluent accepts. It looks like the smaller elements have better orthogonal quality. Note that capture curvature is enabled. Is there a way I can increase the quality without decreasing the element size (and thus staying within limit of the student version)?nnn all throughout the model only the topmost layer of the solid pipe seems to have terrible quality, however the rest of the pipe and internal fluid seems fine.n Is the only way of fixing my mesh quality to decrease the element size?n
    • Karthik R
      Administrator
      Hello,nThe geometry seems simple enough to have a structured mesh (I might be mistaken here but I'm going with the screenshots posted here). You might want to decompose your geometry such that you have a sweepable part. You should be able to use Multizone or Sweep mesh to generate a good structured mesh for this domain.nRegarding the high quality in the solid portion of the pipe, it is because the thickness of the pipe is so small compared to the length. This is the reason for the poor quality. Please see if you are able to create a structured mesh. The advantage is that you can have stretched meshes in the streamwise direction (length of the pipe).nKarthikn
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