Hi @gmohedat, I think personally I would put a wheel representation on and move it closer to the ground to simulate actual flow around the car. I would also give it a bigger bounding box to reduce wall interference. What are you hoping to get from the simulation? Initially, I would simulate as a solid shape instead of a shell, after that you could add inlets/outlets into the body in the appropriate places. I think this would give a better external flow simulation. After you have got good results for an external simulation, maybe add more geometry to do a more detailed analysis on internal flow if you are interested in this much detail?
Looking forward to hearing your thoughts,