Smoke rises?

Author
Discussion

evenflow

Original Poster:

8,800 posts

289 months

Monday 11th November 2013
quotequote all
I'm in a Veyron (or indeed Agera), travelling at 235mph with the strongest gust of wind from Super Typhoon Haiyan behind me.

I wind down the window and hold my lit cigarette out.

Does the smoke rise vertically?

dundarach

5,381 posts

235 months

Monday 11th November 2013
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You'd be sucked out, fag in hand and smiling smile

Impasse

15,099 posts

248 months

Monday 11th November 2013
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dundarach said:
You'd be sucked out, fag in hand and smiling smile
Blimey. How much does she charge for that?

The Nur

9,168 posts

192 months

Monday 11th November 2013
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If that happened and the resultant tail wind was fast enough to negate all downforce generated, would the car rise on it's suspension?

Duke147

629 posts

155 months

Monday 11th November 2013
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Ignoring turbulence and other complicated stuff: If ground speed = 235mph and the wind is blowing at 235 mph from behind then your air speed = 0. Relative to you the smoke will be vertical, but to an observer braving the storm and able to stand still then, no. It would be almost horizontal. :geek:

mrmr96

13,736 posts

211 months

Monday 11th November 2013
quotequote all
Why would it be horizontal to an observer on the ground? Surely it would be a vertical column from the car? You'd see the car and a stack of vertical smoke on top come haring past?

Note these answers do assume that the car and wind are EXACTLY the same speed. You can then say that they are stationary WRT each other. The reality is that this would never happen and there would be massive turbulence outside the open window and the smoke would be so dilute you'd never see it. Also, the cigarette would be pulled from your hand immediately.

dundarach

5,381 posts

235 months

Monday 11th November 2013
quotequote all
Impasse said:
dundarach said:
You'd be sucked out, fag in hand and smiling smile
Blimey. How much does she charge for that?
in a veyron, I image 'a lot' smile

Krikkit

27,003 posts

188 months

Tuesday 12th November 2013
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mrmr96 said:
Why would it be horizontal to an observer on the ground? Surely it would be a vertical column from the car? You'd see the car and a stack of vertical smoke on top come haring past?

Note these answers do assume that the car and wind are EXACTLY the same speed. You can then say that they are stationary WRT each other. The reality is that this would never happen and there would be massive turbulence outside the open window and the smoke would be so dilute you'd never see it. Also, the cigarette would be pulled from your hand immediately.
Correct, a stationary observer (lashed to a telegraph pole to stop the wind pulling them apart) would see a vertical smoke column.

It's just a thought experiment, no-one's really going to drive a Veyron through a wind tunnel to verify any of this.

McWigglebum4th

32,414 posts

211 months

Tuesday 12th November 2013
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But what if you used a conveyor belt?

Duke147

629 posts

155 months

Tuesday 12th November 2013
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Krikkit said:
Correct, a stationary observer (lashed to a telegraph pole to stop the wind pulling them apart) would see a vertical smoke column.

It's just a thought experiment, no-one's really going to drive a Veyron through a wind tunnel to verify any of this.
Edit: yup, vertical column of smoke moving fast. You're quite right! D'Oh!



Edited by Duke147 on Tuesday 12th November 21:45

NEEP

1,801 posts

205 months

Saturday 16th November 2013
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McWigglebum4th said:
But what if you used a conveyor belt?
Hard to smoke a conveyer Belt out the window of a Veyron,

Liokault

2,837 posts

221 months

Thursday 21st November 2013
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How about a burning cig in zero gravity?

I could check this i'm sure but work blocks youtube

mrmr96

13,736 posts

211 months

Thursday 21st November 2013
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Liokault said:
How about a burning cig in zero gravity?

I could check this i'm sure but work blocks youtube
Would you assume that the air in the container is at an equal temperature throughout before you lit the cig?

Remember that hot air rises, because it's less dense. So it moves from an area of high density to low density. Air at ground level is densest due to gravity, so it goes skyward because the upper atmosphere is less dense.

So in zero gravity (or micro gravity as it's really known on a space station) the smoke would still want to move towards the lowest density, which would be nearest to the flame. So I imagine it would form a fuzzy cloud around the cigarette, until it cooled and random motion draws it away.

Asterix

24,438 posts

235 months

Thursday 21st November 2013
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I'd like to see the ciggy lit in the oxygen rich atmosphere of the ISS.

Liokault

2,837 posts

221 months

Thursday 21st November 2013
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I'm sure theres a youtube (again, blocked at work) of a match being struck in zero gravity.

mrmr96

13,736 posts

211 months

Thursday 21st November 2013
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Asterix said:
I'd like to see the ciggy lit in the oxygen rich atmosphere of the ISS.
It's not "oxygen rich".

http://en.wikipedia.org/wiki/International_Space_S...

"The atmosphere on board the ISS is similar to the Earth's.[154] Normal air pressure on the ISS is 101.3 kPa (14.7 psi);[155] the same as at sea level on Earth. An Earth-like atmosphere offers benefits for crew comfort, and is much safer than the alternative, a pure oxygen atmosphere, because of the increased risk of a fire such as that responsible for the deaths of the Apollo 1 crew.[156] Earth-like atmospheric conditions have been maintained on all Russian and Soviet spacecraft"

Asterix

24,438 posts

235 months

Thursday 21st November 2013
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mrmr96 said:
Asterix said:
I'd like to see the ciggy lit in the oxygen rich atmosphere of the ISS.
It's not "oxygen rich".

http://en.wikipedia.org/wiki/International_Space_S...

"The atmosphere on board the ISS is similar to the Earth's.[154] Normal air pressure on the ISS is 101.3 kPa (14.7 psi);[155] the same as at sea level on Earth. An Earth-like atmosphere offers benefits for crew comfort, and is much safer than the alternative, a pure oxygen atmosphere, because of the increased risk of a fire such as that responsible for the deaths of the Apollo 1 crew.[156] Earth-like atmospheric conditions have been maintained on all Russian and Soviet spacecraft"
I stand corrected and informed.

tapkaJohnD

1,993 posts

211 months

Friday 22nd November 2013
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This situation (Veyron in a tail wind) is exactly the same as flying in a balloon basket.
You travel at exactly the same speed as the wind - how could you do anything else?! - so the air appears still. Of course, hot air balloons are heated by enormous canisters of inflammable gas, so smoking is banned in the basket, but I'm sure the smoke would go straight up!
John