/diy/ - Do It Yourself

I recently joined a small german formular student team (20 members) and was assinged to the aerodynamics division. I noticed that the current simulation model of the car is faulty since the radiators are treated as solid objects that do not let air pass through. The values for the radiator were sourced from a test at which the air was moving at a very low speed. Not very representative for a simulation running at 30 miles per hour.
I tried looking up solutions to the problem but i could not figure out how to define a part as porrous or a filter. A description of the progress would be really appreciated. thanks in advance! (pic related is the current car)