Results 1 to 14 of 14

Thread: What Sound Barrier?

  1. #1
    Join Date
    Jun 2000
    Location
    GSBLINY
    Posts
    9,611

    Default What Sound Barrier?



    I'm watching The Right Stuff on Turner, and they just showed Yeager breaking the sound barrier for the first time (I was 1 month old.). I looked it up on Wiki, and found that striking photo, with the filname SonicBoom.jpg.

  2. #2
    Join Date
    Jun 2003
    Location
    Fredericton, New Brunswick
    Posts
    32,636

    Default Re: What Sound Barrier?

    Great photo - thanks.

    Unusual to see you here; feel free to reinstate the habit.
    If I use the word "God," I sure don't mean an old man in the sky who just loves the occasional goat sacrifice. - Anne Lamott

  3. #3
    Join Date
    Oct 2006
    Location
    Livin' in Oz
    Posts
    53,374

    Default Re: What Sound Barrier?

    Does that only happen on high humidity days?

    A friend of mine, who is a politician, is on the armed services liaison program. During a non-sitting week, he spent a week with the air force, flying F-18s. Said that there's no sensation of speed at all when flying at Mach 1+ unless it's done down low - which they did, over the water.
    "Travel is fatal to prejudice, bigotry and narrow-mindedness, and many of our people need it sorely on these accounts. Broad, wholesome and charitable views of men and things cannot be acquired by vegetating in one little corner of the earth all one's lifetime" Mark Twain... so... Carpe the living sh!t out of the Diem

    I'd rather look back at my life and say "I can't believe I did that" instead of being there saying "I wish I'd done that"

  4. #4
    Join Date
    Nov 2008
    Posts
    21,873

    Default Re: What Sound Barrier?

    Does the nose shed shocks or is that an expansion flow behind the shock that causes condensation?

  5. #5
    Join Date
    Jun 2009
    Location
    Northwest Oregon coast
    Posts
    23,656

    Default Re: What Sound Barrier?

    Im watching it now, the director is my wifes cousin , his mom liked me.

  6. #6
    Join Date
    Jul 2008
    Location
    Tacoma, WA
    Posts
    8,169

    Default Re: What Sound Barrier?

    Got any Beeman's?
    “What, Me Worry?". -. A. E. Newman

  7. #7
    Join Date
    Apr 2000
    Location
    Southampton Ont. Canada
    Posts
    5,795

    Default Re: What Sound Barrier?

    ^^^^^
    I can almost taste that.
    Memory is a funny thing.
    R
    Sleep with one eye open.

  8. #8
    Join Date
    Oct 2004
    Location
    oklahoma
    Posts
    2,299

    Default Re: What Sound Barrier?

    We used to hear booms, when i was a kid. It may have been the Air Guard.
    Ask not what your country can do for you; ask what you can do for your country. John Fn Kennedy. (D)

  9. #9
    Join Date
    Apr 2005
    Location
    Hills of Vermont, USA
    Posts
    21,326

    Default Re: What Sound Barrier?

    Wonderful photo! Thanks for posting it.
    "If it ain't broke, you're not trying." - Red Green

  10. #10
    Join Date
    Apr 1999
    Location
    Hyannis, MA, USA
    Posts
    42,944

    Default Re: What Sound Barrier?

    This physics is fun. As the bit from the National Geographic below explains, it's not a shock wave thing and it's not exactly a sound barrior thing. As the photo shows, it does not always form the same way.

    August 8, 2005—A U.S. Navy photographer with lightning-fast reflexes captured this image of a fighter plane blasting through a "sonic boom cloud" as the jet broke the sound barrier. Petty Officer 3rd Class Jonathan Chandler shot the picture as the F/A-18F Super Hornet blew past the aircraft carrier U.S.S. Kitty Hawk in the Philippine Sea on July 27.

    Despite its name, the sonic boom cloud doesn't always come with a sonic boom, and it's not a shock wave of the sound barrier being broken. The clouds only occur in unique weather conditions, when aircraft fly fast enough to cool the air around them, causing moisture in the air to condense into clouds. These halos of vapor appear for only a few seconds when aircraft reach speeds just below or just above the speed of sound (741 miles an hour/1,193 kilometers an hour).

    But you don't have to be a top-gun photographer to see a sonic boom cloud. Several observers reported seeing one two days before this picture was taken, as the space shuttle Discovery reached supersonic speed soon after its July 25 launch.



    https://news.nationalgeographic.com/...ndbarrier.html

  11. #11
    Join Date
    Dec 1999
    Location
    Oriental, NC USA
    Posts
    4,089

    Default Re: What Sound Barrier?

    That picture was on my home page for many years so it is not at all new. First you compress air and then release the pressure. If there is enough moisture in the air and it passes through the dew point while decompressing, there will be a flog of moisture condensation. Its seen by anyone who flies commercial coming off the wing flaps and ailerons when they are at steep angles while taking off or landing. Not sound barrier generated of course but the same physical phenomena. The picture was accompanied by one doing a wingover close aboard at deck level which was scarier. I heard that pilot was grounded. The symmetry of that donut is what amazes me.
    Tom L

  12. #12
    Join Date
    Nov 2008
    Posts
    21,873

    Default Re: What Sound Barrier?

    Quote Originally Posted by CWSmith View Post
    Does the nose shed shocks or is that an expansion flow behind the shock that causes condensation?
    Quote Originally Posted by Tom Lathrop View Post
    First you compress air and then release the pressure. If there is enough moisture in the air and it passes through the dew point while decompressing, there will be a flog of moisture condensation. Its seen by anyone who flies commercial coming off the wing flaps and ailerons when they are at steep angles while taking off or landing. Not sound barrier generated of course but the same physical phenomena.
    So it is an expansion flow, but a shock is not required? Interesting. Good to know. I sometimes show that video to students when I'm trying to get them to picture the Earth's bow shock. I always caution them they are not actually seeing the shock in the photograph, but this better explanation helps.

  13. #13
    Join Date
    Apr 2000
    Location
    Barrie, Ontario, Canada
    Posts
    4,113

    Default Re: What Sound Barrier?

    Yes, it is not uncommon to see forming in the vortices of a large aircraft during takeoff or approach.



    The outboard ends of the flaps are quite angular, so a vortice forms there. And in this photo the wing is demonstrating Bernoulli quite well by forming condensation in the low-pressure above the wing.

    Dave

  14. #14
    Join Date
    Oct 2006
    Location
    Livin' in Oz
    Posts
    53,374

    Default Re: What Sound Barrier?

    Those vortices look a little bit like this



    That's a waterspout in a video that I clipped an image from - got it from the girlfriend's brother the other day.

    We've had a bit of rough weather in the area. I think that one was in the Sunda Strait - he also had an image of a large truck on its side on a ferry - don't know if the waterspout did it, or just rough weather. He had more video of extreme weather where he'd been - Makassar in Sulawesi, whilst installing a ship's radar.
    "Travel is fatal to prejudice, bigotry and narrow-mindedness, and many of our people need it sorely on these accounts. Broad, wholesome and charitable views of men and things cannot be acquired by vegetating in one little corner of the earth all one's lifetime" Mark Twain... so... Carpe the living sh!t out of the Diem

    I'd rather look back at my life and say "I can't believe I did that" instead of being there saying "I wish I'd done that"

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •