Why do passing trucks suck instead of blow?
Nope, it's not the first line of a joke or a rhetorical question. I would expect a passing truck or bus to be pushing a wave of high pressure air in front and beside, but I've noticed time and agai...
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Dick_B wrote:
Nope, you are all wrong.
The real explanation is that the truck IS pushing air against the sides of the trailer and tow vehicle. BUT the least stable part of that assembly is between the trailer wheels and the hitch. When that part of the assembly is pushed away from the truck it tends to also move the back of the tow vehicle away from the truck which tends to turn the front of the tow vehicle TOWARDS the truck thus giving the impression of the truck sucking in the tow vehicle.
You're welcome.
Sorry but the effect is the same for cars, trucks and other vehicles. This is why if you look at the nose cone of any launch vehicle (a rocket to you) it is not a sharp point but a dull rounded shape. In fact that shape is one of the most design intensive parts of the vehicle.
What it does is create a bow wave of air which creates a low pressure area behind it. This reduces drag all along the length of the Launch vehicle. Resulting in less fuel required to exit the atmosphere.
And the others are correct this is what is happening when a truck passes you.
If you are really attuned to your vehicle you will feel the initial push of the bow wave, then comes the low pressure area or feeling of being pulled in.
This effect is easily and readily accommodated when towing when you know what to expect. And why it is happening.
