Timeline for Does Bernoulli's Equation make Wind Tunnels Inaccurate?
Current License: CC BY-SA 4.0
12 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Nov 21 at 14:32 | comment | added | Solomon Slow | @FluidizedPigeonReactor, Bernoulli's equation doesn't care about the location of the blower, but the blower moves air by creating a pressure differential. Pressure on the inlet side of the blower is significantly less than the pressure on the outlet side. If you create a wind tunnel with the blower positioned to force air in to the tunnel, then switching it on will raise the pressure of the air in the tunnel. (Bernoulli says, it won't raise it by as much as if the outlet were blocked so that the air cannot flow.) If the blower sucks air out from the tunnel, then that reduces the pressure. | |
| Nov 21 at 14:23 | comment | added | Solomon Slow | @FluidizedPigeonReactor, Yes, but "1 atmosphere on Earth where? The pressure of still air in Denver, Colorado is only about 80% of the pressure of still air on a beach somewhere. And, that's really only an average figure because air pressure in both of those places varies with the weather. | |
| Nov 21 at 12:41 | history | reopened |
Vincent Thacker gandalf61 Michael Seifert |
||
| Nov 21 at 2:56 | comment | added | Ján Lalinský | > "we find that the pressure inside a wind tunnel should be lower than that of atmosphere. " No, because you can't apply the Bernoulli equation across an active fan. Wind tunnel has a big fan, which accelerates air, and can create both fast flow and increased pressure downstream (this effect is called compression and it is used e.g. in jet engine). | |
| S Nov 21 at 2:26 | review | Reopen votes | |||
| Nov 21 at 12:41 | |||||
| S Nov 21 at 2:26 | history | edited | Fluidized Pigeon Reactor | CC BY-SA 4.0 |
Fixing "need more clarity"?
Added to review
|
| Nov 21 at 2:19 | comment | added | Fluidized Pigeon Reactor | The pressure of still air is 1 atmosphere on Earth. Bernoulli's equation does not care about where the pump is, as far as I know. | |
| Nov 20 at 19:45 | history | edited | Qmechanic♦ |
edited tags
|
|
| Nov 20 at 18:23 | comment | added | Solomon Slow | What is the pressure of "still air?" Also, do you suppose it depends on whether the blower is positioned to force air in to one end of the tunnel or, to pull air out from the opposite end? | |
| Nov 20 at 17:32 | history | closed |
hft Buzz♦ |
Needs details or clarity | |
| Nov 20 at 17:03 | review | Close votes | |||
| Nov 20 at 17:32 | |||||
| Nov 20 at 16:42 | history | asked | Fluidized Pigeon Reactor | CC BY-SA 4.0 |