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Pickup airflow
I'm still not set up for CFD yet. Meanwhile, I've given considerable thought to the distribution of airflow around my truck. I finally did some napkin calculations. Based on size and shape of respective surfaces and areas I suspect to a first order approximation the air displaced by my 02 Tundra 4WD is roughly as follows.
Under: 10%
Sides: 30% each (x2)
Over: 30%
Of the 30% on each side I suspect about 10% goes past the windows and 20% goes past the lower sides up to tailgate height. When I consider gradients from higher to lower where those areas meet along upper and lower surfaces, those numbers seem consistent with how mist and rain flows over those transitions as well as points from which wake additions seems to originate at least from what I can see in mirrors. These observations give me some confidence that I may not be too far off with this approximation.
For the sake or argument, let's suppose these numbers are close. Then it provides an interesting viewpoint for where to mod the truck. An areocap could improve half the air flow (30+10x2=50%). Of that top shape seems clearly more important than side shape. This agrees with aerocap designs and performance reports from members here BTW. These numbers also suggests that wheel skirts and belly pan mods might address about 30% (10+20/2x2) of total airflow so less potential gains there.
I'm very curious what methods others might have used to break down, either approximately or precisely, the distribution of airflow over their trucks. We can't do too much comparison across makes and models of course but I think it would be interesting to compare methods nonetheless.
Cheers
KB
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