first grid size and y-plus
 

hi
i am going to model a turbulent flow over a flat plate.
if i want to extract a given y-plus, how can i set the first grid size?
is there any formula to calculate the distance between wall and first grid in a given flow?

thank you in advance

Hi,
You can estimate first grid size and calculate problem in your solver. Then you should check y+ value in the first cell near wall. Depends on this value you can refine mesh (or use automatic mesh adaptation option in your solver, for example Fluent). It is iteration process. Typically one preliminary calculation is sufficient to ensure adequate y+ value in the first cell.

Regards,
doodek