3
$\begingroup$

I am standing indoors, right in front of my open window, as I see my curtains moving back and forth and I can hear my closed doors shaking. I can also hear the wind howling loudly.

Why don't I feel this wind/air moving back and forth? I can see and hear it, as described above, but my body doesn't feel any of this flowing wind. Maybe this has something to do with the window screen?

If I am outdoors, of course, I immediately feel the wind.

Please explain this as if you are talking to someone who knows nothing about physics (which is the case for me).


Related question on Physics SE:

"Why does my door shut faster when the window is open?"

$\endgroup$
  • 1
    $\begingroup$ In the same situation you described, I can feel an air flow. Perhaps you don't notice as the air streams outdoors you are uses to have hardened you. $\endgroup$ – Gyro Gearloose Feb 28 '16 at 21:04
  • $\begingroup$ "I can hear my closed doors shaking." ... is there an opening opposite to your open window where the air could leave? This makes a huge difference. I often ask myself, "why are the shutters rattling" when the window behind is shut and within any reasonable scale, airtight? $\endgroup$ – Gyro Gearloose Feb 28 '16 at 21:29
3
$\begingroup$

Assuming the doors are shut and you are not very close to the window, then:

  • there is no significant movement of air through the room as the doors are shut and it has nowhere to go, so you feel no wind;

  • there are significant pressure changes in the room, which is enough to cause the doors to rattle, which are actually rather small pressure changes as the pressure is exerted over the whole surface of the door;

  • there is significant turbulence near to the windows as moving air outside interacts with still air inside, and this turbulence moves the curtains.

$\endgroup$
  • $\begingroup$ My window is literally barely open—just a 3 inch crack. (When I open my window fully, I do feel the wind.) Yet, even with this small opening, doors close, closed doors rattle, and my curtains are constantly moving. How can such a small opening affect my room's air pressure so much, yet I don't feel a thing, even right in front of the window? $\endgroup$ – Kyle Feb 28 '16 at 21:38
  • $\begingroup$ @Kyle !!! keyword: "my curtains are constantly moving" !!! If there was a (net) airflow, the curtains would not be moving but blown in (or out) more or less constantly. So there is no wind but only a (periodic) pressure change. $\endgroup$ – Gyro Gearloose Feb 28 '16 at 21:46
  • $\begingroup$ @Kyle: well, if the wind is at the top end of a force 3 ('light breeze') then with reasonable assumptions (3 inch gap, half a metre wide) it would want to move about a cubic metre of air into the room every five seconds, other things being equal. It can't do that, because the doors are shut, but it definitely will make them rattle. (Sorry for the mish-mash of units.) $\endgroup$ – tfb Feb 28 '16 at 22:58
  • $\begingroup$ Any further explanation as for exactly how the turbulence moves the curtains? $\endgroup$ – Zach Saucier Mar 1 '16 at 22:09
  • $\begingroup$ @ZachSaucier: not in detail: I guess that there's just a fair amount of air moving in the region of the window, and it picks up the curtains. What there isn't is bulk airflow through the room $\endgroup$ – tfb Mar 1 '16 at 22:30

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.