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R.Abd October 2, 2010 07:26

Maximum of Mesh Size
Dear All,

I am studying mesh generation of domain. I studied Wall Function and know somethings about mesh size on boundaries but unfortunately, I cant find some formula about maximum size of mesh that can use in a domain for example relation between Mesh size to Re, Turbulent intensities, . . .
Whats your idea or reference?
With regards,

PSYMN October 3, 2010 14:16

Max size is a limit, not a goal or requirement.
Use the largest max size possible, but use your max ratio to limit growth...

For instance. If I had size 1 mesh at the boundary, I could set the max size to 1024 and my ratio to 1.2. Then just let the math work its way out. The max size is not forced (and may not be reached), it is simply a limit. My mesh will start to grow into the volume and will stop either when the volume is full (short of reaching my max size), or when my max size is reached, the ratio will reduce to 1 and continue at that size until the volume is full.

I usually set my max size to much larger than I actually think it will reach. The exception is if I plan a tet to hex conversion and want the mesh to stop transitioning for most of the volume.

Also keep in mind that you may also have regions in the volume that need their own local max size. This can happen in a wake or other area where you want to ensure that the mesh is fine enough to capture your physics. In that case, use a density box (ICEM CFD terminology) to control the max size locally.

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