blasius boundary layer velocity profile question

[pmv1]

I'm trying to save processing time with ANSYS 15.0 by creating my own velocity profile after the boundary layer develops (the problem is flow over a hemisphere on a flat plate). I need to determine a point to place the mesh inlet when I generate the CFD mesh that is close enough to the hemisphere to save solution time, but far away enough to avoid the boundary layer at the inlet being disturbed by the presence of the hemisphere. I would appreciate any advice on how to determine this optimal position for the mesh inlet using the blasius solution.

Thanks,
pmv1

 

[rb1957]

it sounds to me like you want to replace the hemisphere with a volume = hemisphere+BL. i think this shape will be way more complicated than a simple hemisphere ... maybe what you gain on the swings (saving the CFD from doing the BL calc) you'll lose on the round-abouts (trying to describe the hemisphere+BL shape). and the BL depth is proportional to the local velocity (which is compicated, changing, and estimated at this stage).

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