Why do passing trucks suck instead of blow?

Vulcan Rider wrote:
Some person, supposedly on the NASA payroll, wrote that. I certainly hope it doesn't represent an "official" position from them because......it is absolutely wrong.

The Bernoulli principle only applies to a specific set of circumstances: an enclosed tube and fluids. It is what makes carbs work....and some atomizers and some paint "guns".

The space between vehicles is not enclosed AND the things being "moved" are not fluids; they are big chunks of metal.

How can you say Bernoulli only applies to an enclosed tube and fluids and follow up with a carburetor as an example?? A carburetor venturi is an hourglass-shaped (i.e. necked down) airflow device. When the intake air passes through that confined space, the pressure drops. Fuel flows because the float bowl vents are at atmospheric pressure while the pressure in the airflow within the venturi is lower. It's actually a great comparison to two vehicles travelling beside each other.

When you say the vehicles are moving and the air isn't I agree but aerodynamics is all about the relative difference in speeds between the air and the objects. That's how wind tunnels are used to test out real world performance. The only difference between the wind tunnel and heading down the road is the air speed relative to the road surface, which is negligible compared to what's going on around the vehicles themselves.

If, as you claimed, more air in a smaller place always creates higher pressure, how do you explain the concept of a diffuser on a race car? Diffusers cram all kinds of air into a small space under the car to help "suck" it down to the track.

If you write NASA to tell them they're wrong, you'd better add a bunch more to your list.

http://www.caranddriver.com/features/the-physics-of-diffusers-how-to-make-a-car-really-suck-feature

http://www.racecar-engineering.com/technology-explained/diffusers-engineering-basics-aerodynamics/

https://en.wikipedia.org/wiki/Diffuser_(automotive)