undefined | Better HN

0 pointsori_b10y ago0 comments

> Bernoulli's principle is a real thing and will add to the lift a wing generates without contributing to any net motion of the air upward or downward.

The compression of the air below the wing moves it downwards, more or less. There are no ways to get around Newton's laws of motion (barring relativity, and planes aren't fast enough for that).

0 comments

3 comments · 1 top-level

deciplex10y ago· 2 in thread

After the wing passes, the air is no longer compressed, and the net motion of the air is unchanged from before it encountered the wing. What then?

Anyway, I'm not saying you're wrong, I'm just saying that thinking about the individual forces involved leads to more complexity than necessary (this is usually the case). It's much simpler to just consider the energy going into the system and derive the net work produced from that.

ori_bOP10y ago

> After the wing passes, the air is no longer compressed, and the net motion of the air is unchanged from before it encountered the wing. What then?

Then, there would be no lift generated, since there is no acceleration of mass.

1 more reply

jameshart10y ago

After the wing passes, the air is probably warmer than it was before the wing passed through, so the net motion is changed.

j / k navigate · click thread line to collapse