Fluent validation test for calculate the drag of a car
 

Hello. This is my first post (and sorry for my english). I want to calculate the drag of a car, but i'm not sure if i'm doing the calculations well. For that reason, i want to check the drag of a simple body (like a sphere) and check if the drag coefficient is correct. In this case, i will know that the Fluent configuration (viscous model, calculation, mesh, etc..) will work for a car. So, i have this questions for make a case of a simple body:

• How must be the mesh? mesh only with a size function is a good way to mesh a sphere, or i must to put boundary layer too?
• In Fluent, what's the best viscous model to do the calculation? K-epsilon or S-A?
• I need to modify something, like calculation options, solver, boundary conditions, etc?
• The most important: I've get some drag coefficient doing various tests with some simple bodies at different reynolds number, but i don't know what is the real valour for the drag coefficient of this bodies, to know if i'm doing well the configuration. (normally i use a sphere to do the test)

So, basically, i need to know how configure Fluent to do a external test of a sphere (or other body), and what is the valour Fluent must give me. So i will extrapolate to other cases. When i have this information, i will do the test for a car.

Thanks for your help!!