YPlus Value
 

I am working on external flow of finned projectile in subsonic range, and use SST model for turbulence. I used Y+ value of 64 and also of 1.5 with hybrid mesh but my results are not compared with experimental. I use reference pressure 1atm and mach number is 0.5.
My inlet intensity is medium
Can anybody help me why its happening

I'm not familiar with your case, but you may can try large region of Yplus(i.e. from 0.01-5, name it, 0.01/0.03/0.06/0.09/0.15/0.3/0.6/0.9,,,, or just typical value of those), just for sensitivity analysis, may find a good region of it.
Just try some small Yplus value, see if have significant influence on interested variable.

Thanks for quick reply.
I worked on guided 155 finned projectile.
the servo fin and motor fin are both opened, and i used hybrid mesh for creating grid in ICEM CFD.
Will the hybrid mesh effect CP value. when my Wall Y+ is less than 100 then my results match but when Y+ is 1 then it deviate.
What i do?
also can you help me in mesh making