Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Water Weak behind Aircrafts

  1. Jun 4, 2005 #1

    Clausius2

    User Avatar
    Science Advisor
    Gold Member

    Everybody has seen the weak of condensed water which is left behind an aircraft when it flies in air.

    To say the truth I am not an specialist in Aeronautical stuff, so I am searching a brave who tells me from where this weak comes from:

    -does it come from the products of combustion (H2O released in combustion reaction)?

    -does it come from the condensed water vapor present in surrounding air, due to the pressure exerted by aircraft structure on flight in the air flow?

    Thanks in advance.

    This ignorance is killing me..... :rolleyes:
     
  2. jcsd
  3. Jun 4, 2005 #2

    brewnog

    User Avatar
    Science Advisor
    Gold Member

    Ahoy there Clausius,

    Do you mean vapour trails? [​IMG]

    If so, it's just hot water vapour being emitted in the exhaust gases, and cooling. As you can see from the picture, they only emerge from the engines. You only get them at high altitude (troposphere, I think), so they're going to be either condensed, or actually frozen (which explains why they're visible). I suppose the actual source of the water is partly a combustion product, and partly water vapour held within the air just being heated up. You know more than me about gas turbines, but I suspect that in a typical commercial turbofan, the amount of water vapour being emitted due to combustion is much less than that which was in the air anyway, and has just been heated up.

    The only other thing I can think you might mean is a sonic boom, like this: [​IMG]

    If so, you know much, much more about that than me, but I don't think that's what you meant anyway. The reason you might have had trouble Googling your question is because you meant to type "wake" not "weak". :smile:

    Take care.
     
    Last edited: Jun 4, 2005
  4. Jun 4, 2005 #3
  5. Jun 4, 2005 #4

    brewnog

    User Avatar
    Science Advisor
    Gold Member

    I'll remember that Huck, thanks!

    We have a game going on at the moment whenever we're sitting outside our house. We lie on our backs, and watch, urm, contrails forming, and make bets on where they're going from and to.

    "Ooohh, I reckon that one's Oslo to New York"
    "Nahh, more like Copenhagen to Boston..."

    Hours of fun!
     
  6. Jun 4, 2005 #5

    Clausius2

    User Avatar
    Science Advisor
    Gold Member


    :blushing: :blushing: :blushing: Ufff..... Sorry, you're right. I was confused about that word, I recall it begun by letter W, but I was not sure.

    Now I am going to teach you some of spanish. In this kind of situations one usually says:

    :blushing: Vaya metedura de pata!!

    BTW: thanx for your explanation.
     
  7. Jun 4, 2005 #6

    brewnog

    User Avatar
    Science Advisor
    Gold Member

    Didn't mean to embarass you, but if I wasn't speaking my own tongue I'd pretty much expect people to point out my mistakes. Also I thought it might help with your search. :smile:


    Ok, I'll give it a go...!

    De nada! :smile:
     
  8. Jun 5, 2005 #7

    GENIERE

    User Avatar
    Science Advisor

    Not that I understand it, but I believe the photo is demonstrating THE PRANDTL-GLAUERT SINGULARITY and need not be due to supersonic airflow.

    http://www.galleryoffluidmechanics.com/conden/pg_sing.htm


    ...
     
  9. Jun 5, 2005 #8

    Clausius2

    User Avatar
    Science Advisor
    Gold Member

    Yes, you're right. Anyway the purpose of this thread was not any sonic boom. Brewnog tried to expose it thinking I was referring to that. I am happy with his first explanation.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Water Weak behind Aircrafts
  1. Military aircraft (Replies: 1)

  2. Subsonic aircrafts (Replies: 6)

  3. Aircraft Wings (Replies: 2)

  4. Aircraft inventions (Replies: 10)

  5. Tail of an aircraft (Replies: 3)

Loading...