Air motion in an automobile...

[Externet]

Hi all.

 

Noticed lately that when turning a corner, the temperature of the air inside the car feels abruptly warmer [yes, am at the southern hemisphere right now, using airconditioner]

Has to be that layers or portions of the air next to perhaps the windshield does not rotate 90 degrees and is clearly felt at the driver position, by the inertia of the air mass.

If other reason, please explain. That brings the question of a housefly hovering in the car; would it collide with the front windshield on a sudden stop ?

[JohnStu]

Yes when turning, fast enough that is, the air inside get more windy, so, if the air is hotter than your skin, then it would feel like hot air, or are you just talking about air becoming hotter than before, then that could be hot air trapped finally able to move around more. I assure you the average temperature of all air molecules only increase by a bit when u turn your car. So, wind is the cause, created by the fast turning.

[MigL]

Possibility 1 : the springs in your vacuum actuated vent valves have weakened over time ( is this an older vehicle ? ) and swing from the a/c position to the heater position when turning in one direction.

Possibility 2 : since the vent valves are vacuum actuated, accelerating out of the turn opens the throttle decreasing available vacuum signal to the vents. Try accelerating in high gear uphill to see if this is the problem.

 

I know of no way a change of direction will change air temperature.

 

The fly is at rest with respect to the air in the vehicle. which is at rest with respect to the vehicle. Any acceleration or force experienced by the vehicle will also affect all occupants, human or insect.

[davey2222]

Turning produces acceleration (= artificial gravity directed outward). Warmer air, being less dense than air-conditioner air, moves inward, hence the rise in temperature if you are sitting there.

[Externet]

Just to clarify... All windows are shut. No outside air interacting with the colder air inside.

It was just an observation, turning the car as in a 90 degree corner does not make the air inside to turn 90 degrees with it.

[ewmon]

Turning produces acceleration (= artificial gravity directed outward). Warmer air, being less dense than air-conditioner air, moves inward, hence the rise in temperature if you are sitting there.

I agree with davey2222, it's somewhat like a swing carousel ride at an amusement park. The heavier air that's usually in the lower part of the car will move to the side of the car opposite the turn (eg, moves right when turning left), forcing the warmer air to the side of the car in the direction of the turn (eg, moves left when turning left).

 

[tvp45]

Yes, I throw my vote in with ewmon and davey2222. The effect can be readily seen by using a helium birthday balloon, which "rises" in the direction of acceleration in the same fashion as heated air. The layer of air adjacent the windows would of course be heated.