Is this algebra, or physics?

I was taking a break and I noticed a car at a stoplight. The car was heading north, and the US Flag was blowing towards the north. This got me to wondering. If the wind remained constant, ie, same direction, same speed, would the flag appear to not wave if the car was traveling at the same speed and direction as the wind? The light turned green, and although I wasn’t able to see the whole outcome, at one point the flag did seem to ‘droop’ as the car was accelerating.

So, if I was heading south at 15 mph, and the wind was doing the same, would my flag not wave?

(I didn’t post this to any other group because I thought this was rather mundane and a bit pointless, because, well, I was on break!)

If the airflow wasn’t turbulent, maybe. That would mean that the wind just blows in a straight line from the rear of the car, and the flow of air at the flag from the front of the car was in a straight line, and the two straight lines were exactly lined up with and opposing each other.

But the problem is, over a certain speed (not doing the calculations, and it’s not just a matter of speed anyway), fluid flow becomes turbulent, and it won’t flow in a straight line anymore. Therefore, the flag would flap in various directions as the turbulent airflow hit it.

That’s my explanation. It’s been a while since I was a physics major, so it’s the best I can do without resorting to reference works (I am at work, after all).

The flag should not wave to one side as if one wind speed was signifigantly greater than the other, but will, by no means, stay calm and flaccid. Its material and connection to the pole will put it in a constant state of change. Besides that, there are too many variables to really keep it stable for any signifigant period of time. An easier way to go about this would be to center a piece of laminated paper between two fans, and attach it to a pole on one side. If the fans both generate wind with the same velocity, than the piece of paper would stay still. This is definitely a physics problem.