[excusemeflow]

Hello folks, I'm a complete newbie to this. I'm looking for a little guidance in setting up some simulations, basically I'm looking to run virtual windtunnel calculations.

My goal is to use a simplified model of a race car's body to evaluate the overall affect of various diffuser angles and shapes on the back of the car with regard to drag and downforce production.

My vehicle body is approximately 12 ft long by 4.5 ft wide, and I have a ride height of 2" set up, with symmetry along the Y axis to reduce the calculation time. I am also using a moving ground plane set at the air speed.

What size computational domain would be appropriate for such a vehicle? How many cells would be required for the analysis to accurately model the trends of drag/downforce for a model of this size? Can anyone point me to some information on narrow gap size settings?

Thanks!