[hat_man]

Sorry for a confusing title but my simple mind couldn't figure out a better wording.

I guess what I am wondering about is, is it (to an extent) as beneficial to direct airflow unattached as it is attached?

The example I am seeing is this. We know an aerpcap on a pick up it the best for aero. Airflow stays attached and is "shaped" for lack of a better term. But the cab spoiler/half tonneau is rather close in benefit, but seems unattached so that flow is maybe more "influenced".

If this is the case, then could the same principle apply to say the underbody of the same pickup. Rather than a full belly pan (attached or "shaped") but rather a fin arrangement, directing or "influencing" the flow outward as opposed to directly under.

We know that an air dam is the way to go, so this isn't a real world application. Just a mental exercise I guess so I can try and learn something.

Thanks for any insight.