Fluids

Fluids

Fluent Y+

    • btingthewind
      Subscriber

      Dear sir,


      Recently I'm doing a Fluent turbulent flow simulation with the KW SST turbulence model, before the simulation I specified a y+ value of 1 to aquire the height of the first mesh layer and the boundary layers is 10. However, after the simulation coverged, I checked the Y+ value and found its maximum  was 24. Obviously, there were something with my simulation, but I don't know what to do next.  Shoud I  reduce the y+ to less than 1 or increase the boundary layers greater than 10?


      BEST REAGRDS

    • DrAmine
      Ansys Employee

      Try to keep it low with at least 10-15 cells in the boundary layers.

    • btingthewind
      Subscriber

      THX Sir,


      The detailed boundary layer parameters in my recent simulation are:


      initially specified Y+ value=1


      growth rate=1.2


      boundary layers=10


      first layer height=2.7989e-03mm


      And the minimum orthorgonal quality and maximum skewness of my mesh are 0.151 and 0.89.


      What you mean that I should increase the layers greater than 10 and reduce the y+ value less than 1 to have my problem resolved? Or should I do something else?


      BEST REGARDS,


      BTW

    • Rob
      Ansys Employee

      Assuming the higher y+ values are where they matter (ie on a region you're interested in) you can either remesh the whole model or use adaption to refine the mesh where needed. I'd tend to favour the latter, and it's covered in the documentation. 

    • btingthewind
      Subscriber

      Thank you Sir,


      I'm going to try your suggestions!


      Also, another quetion is that the mesher I used is WB meshing, during my meshing, both the mesh methods of sweep and patch dependent tetras are applied, would the mesh generated by these methods conflict with the mesh adaption?


      Have good days!


      BEST REGARDS,


      BTW

    • Rob
      Ansys Employee

      No. Poly mesh can cause problems, but that's also fixable in Fluent. 

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