[kev11]

Hello all,

First, this is my first post, so I hope I am asking this in the right spot!

I am new to STAR CCM and have a question about AMR. So I currently have a mesh running for an aircraft. I am using AMR to capture the shocks at supersonic speeds. For a little background info, I am multiplying the Mach gradient by the adaptiveMeshSize to determine my AMR criterion.

AMR works very well to capture the shock; however, I am getting refinement in areas I don't want refinement, such as on the fuselage surface, wing, tail, ext. Is there any way I can fix this problem? I want AMR to work in specific areas, and I am not sure on how to go about this problem. I would assume there is a way to have AMR work only in areas a certain distance from the surface?

[LuckyTran]

You need to build on your field function that you are using for refinement to include the additional criteria and it will likely involve a bunch of nested boolean conditions.

For example, the distancetoSurface function will calculate the distance of an arbitrary cell to a surface you select. You can then create your refinement function to be, if the distance is less than some number, then use a small size if the grad condition is satisfied, else, make a really big cell.

You can also use shape parts and incorporate these into the field function to declare regions that should or should not have refinement

Don't be afraid to make 15 user defined functions and 30 if ?'s in Star if that's what it takes to implement your idea. It doesn't have to be all done in 1 unwieldly, unprogrammable function.

[kev11]

Thank you so much for the fast reply!

How do I go about creating this distancetoSurface function you mentioned? The only field functions I see with distance are the "deviationDistance.AutomatedMesh" and "DeviationDistance.Root."

I apologize once again, I am new to STAR so I appreciate your help!

[LuckyTran]

distancetoSurface is not a field function like pressure, temperature, etc.

distancetoSurface is a programming function that you can use when you create a field function. For example, ceil(), floor(), sin(), cos(), etc etc

[kev11]

I am still having trouble having the AMR refine areas of interest on my aircraft. I just want to capture shocks, but the AMR is refining areas on the wing, fuselage, any surface with high changes in Mach (which was my criterion). Since I am running a sim on a half geometry, is there any way I can apply the AMR to the symmetry plane only?