[orange4boy]

And then you place in front of that area a fan generator, is there more force pushing against your truck now than before?

Unfortunately, yes.

A wind turbine creates a lot of drag. They are basically air brakes. The job of a wind turbine is to turn the mechanical energy of air movement into electrical energy. In order to do that it requires a lot of surface area and it has to create a lot of lift or pressure differential which means it creates a lot of drag. The relatively low efficiency of the blades coupled with the low efficiency of an electric motor means a whole lot of energy is lost to drag and heat and that's before it passes the bodywork of the car. If you have ever flown a plane with a variable pitch prop you can immediately feel the huge differences between a free wheeling prop (very high drag), a stalled prop (much lower drag) and a feathered prop (low drag). And remember, this is after you have inefficiently converted energy from fuel to motion already and now you want to change it back again with added inefficiencies.



Then, because the air still flows around the body following flow lines, it does not act like some kind of fairing. The disturbed air flows around the vehicle just like it would have without the turbine, acting on it and creating the same drag as before but now you have to add the drag of the turbine.

The upshot is that a turbine would increase your CD a lot.

Welcome to the forum!