1. jehardiman
    Joined: Aug 2004
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    Location: Port Orchard, Washington, USA

    jehardiman Senior Member

    Cycloidal waves and wakes are entirely different things. The first is caused by tensor shear at the surface, the latter by specific energy input. As I said in post #10, get a copy of Weigel if you really want to get into the difference.
     
  2. Anthony Appleyard
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    Anthony Appleyard Anthony Appleyard

    Thanks. I have already ordered a copy of it.
     
  3. gonzo
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    gonzo Senior Member

    If you observe the wake shape, it will be apparent that it has a crest and it looks like a wave breaking in shallows.
     
  4. Leo Lazauskas
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    Leo Lazauskas Senior Member

    Another very good (free) reference that is available online is:
    Wehausen, John V. and Laitone, E.V.,
    Surface Waves
    Encyclopaedia of Physics, Vol. IX, pp. 446-778
    Springer Verlag, 1960.

    http://coe.berkeley.edu/SurfaceWaves/
     
  5. Anthony Appleyard
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    Anthony Appleyard Anthony Appleyard

    Thanks. But http://coe.berkeley.edu/SurfaceWaves/pdf/errata.pdf is a worryingly long list of errata (around 120 errata); I just checked the first two errata in that list and they have not been corrected in the online version.

    Most of those errata are serious errors in equations, not ordinary-book-type trivia such as "und" for "and".
     
  6. Leo Lazauskas
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    Leo Lazauskas Senior Member

    Yes, those errata have been compiled over many years. Unfortunately, you
    have to go through and correct the text yourself. It's very tedious but the
    book itself is still one of the most cited works in the field.
     
  7. Anthony Appleyard
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    Anthony Appleyard Anthony Appleyard

    I would have done that, with a pencil, if I bought the book on paper; but where to get a .pdf-file-editor?
     
  8. Anthony Appleyard
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    Location: England

    Anthony Appleyard Anthony Appleyard

    While the wake is being directly pushed by the boat, it is likely somewhat different from an ordinary water wave, similarly to a supersonic shockwave in air as distinct from after that shockwave has settled down into ordinary loud soundwaves.
     
  9. Leo Lazauskas
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    Location: Adelaide, South Australia

    Leo Lazauskas Senior Member

    And even more so in finite depth water when the boat passes through the
    critical depth-based Froude number. That number plays a role similar to the
    Mach number in aerodynamics. See, for example:
    http://www.cyberiad.net/wakerowfd.htm
     
  10. Leo Lazauskas
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    Location: Adelaide, South Australia

    Leo Lazauskas Senior Member

    It was important enough for me to print out and annotate myself.
    I think you will get enough out of the Wiegel book as a start. The book by Lamb
    suggested by jehardiman is an absolute classic, but a little archaic and very
    tough going in parts.

    Have fun!
     

  11. Anthony Appleyard
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    Anthony Appleyard Anthony Appleyard

    Thanks for all your information, which I have studied well. But, again, please, as a starting point for the ratio-type equations:-

    (1) If a simple wave-train is moving on deep water under Earth gravity, and the only mathematical component has wavelength = one meter, how fast does it move in knots or in meters per second?

    (2) If a boat or ship is going at 10 knots on water under Earth gravity, in each side of the V-shaped wake, what is the wavelength of the main visible waves?

    If I know the answer for one case, I could use the ratio equation to find the answer for all other cases.
     
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