Export Minimium Wall distance

AshwaniAssam · March 22, 2019, 04:56

Can pointwise export the minimum wall distance for each cell of the mesh? Or is there any other mesh generator which does so?

This minimmum wall distance is required in turbulence model like SA, SST, etc. My point is if we can get the minimum wall distance from the mesh generator we may avoid doing it in the solver.

Thanks

RcktMan77 · March 22, 2019, 16:42

Most modern implementation's of Menter's SST turbulence model, which combines the k-omega and k-epsilon models such that the k-omega model is used on the inner region of the boundary layer and the k-epsilon model is used in the free shear flow, use an automatic wall treatment scheme which applies the correct wall treatment based on the local y+ value.

That being said, in Pointwise you are explicitly providing the wall normal spacing, whether that means you're explicitly setting the end spacing of a connector that is normal to a wall boundary, or if you specify the initial spacing and growth rate for wall type boundary conditions in T-Rex or extrusions. In other words, you should know what this value is as it is a value that you have calculated already for the specific flow regime you intend to use throughout the computational domain. I believe there is even a custom boundary layer profile Glyph script where users can prescribe a laminar or turbulent boundary layer profile to be used in conjunction with T-Rex.

Alternatively, you can use the Examine tool to view the Edge Length metric to help survey the initial spacing near wall boundaries.

March 22, 2019, 04:56	Export Minimium Wall distance	#1
AshwaniAssam Senior Member Ashwani Join Date: Sep 2013 Location: Hyderabad Posts: 154 Rep Power: 13	Can pointwise export the minimum wall distance for each cell of the mesh? Or is there any other mesh generator which does so? This minimmum wall distance is required in turbulence model like SA, SST, etc. My point is if we can get the minimum wall distance from the mesh generator we may avoid doing it in the solver. Thanks

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March 22, 2019, 16:42		#2
RcktMan77 Senior Member Zach Davis Join Date: Jan 2010 Location: Los Angeles, CA Posts: 101 Rep Power: 16	Most modern implementation's of Menter's SST turbulence model, which combines the k-omega and k-epsilon models such that the k-omega model is used on the inner region of the boundary layer and the k-epsilon model is used in the free shear flow, use an automatic wall treatment scheme which applies the correct wall treatment based on the local y+ value. That being said, in Pointwise you are explicitly providing the wall normal spacing, whether that means you're explicitly setting the end spacing of a connector that is normal to a wall boundary, or if you specify the initial spacing and growth rate for wall type boundary conditions in T-Rex or extrusions. In other words, you should know what this value is as it is a value that you have calculated already for the specific flow regime you intend to use throughout the computational domain. I believe there is even a custom boundary layer profile Glyph script where users can prescribe a laminar or turbulent boundary layer profile to be used in conjunction with T-Rex. Alternatively, you can use the Examine tool to view the Edge Length metric to help survey the initial spacing near wall boundaries.