Refinment Level for Vehicle External Aerodynamics
 

Hi,
first i say i'm new both in using OpenFOAM and studying aerodynamics problems (i'm an energy engineer), but i've to do it!
I want to ask to you some tips about the meshing process on that kind of process.
I use AutoHexMesh as mesher and i would like to know which refinment level can i set up for the different parts of vehicle geometry (bumper, hood, windows, wheels, body, ...and so on), and in what range they could be change, because i have to create 3-4 pre-set mesher to study a case completely.
Thank you in advence!
Best regards.