[stillsearching]

Assuming I am starting with something like a box trailer, or a flatbed with a completely cubic load, what kind of aerodynamic treatment is appropriate to make?

The boattail out the rear is fine and a given, what i'm curious about is the front. I've seen some fairly blunt nosed designs under the argument that as long as laminar flow is maintained, that means low drag, and although bulbous a surprisingly flat front can still move air out of the way adequately enough (with a smooth tail) that 'needle nose fronts' arent needed until higher speeds.

Assume i'm working in cardboard, and maybe some thin scrap wood for structure if needed, if it matters...

Assuming a theoretical load of 8 feet wide, 8 feet tall, and 16-20 feet long, how long of a boattail would you make, what kind of work should I do to the front of the trailer mass to have it cut through the air better? Wedge pushing air to both sides, single wedge pushing air up (assuming it sticks out above the tow vehicle) smooth bulbous lump sticking forward... 1 foot? 3 feet?, etc?

How might this change if i'm trying to blend the flow from a pickup which is hauling the trailer, is it acceptable for the air to go 'down' into the pickup bed then back up to the trailer, or would having a topper on and trying to blend the sides/back of that to the actual 8x8 foot stack be better design?


For that matter how do you people model all this stuff up to know anyway, is there some freeware CAD program doing airflow that I can play with designs to learn how to aero-cize any load I might move in the future?