ZGREEN - Wave Patterns made by Havelock Sources

Discussion in 'Software' started by Leo Lazauskas, Jan 3, 2011.

  1. Leo Lazauskas
    Joined: Jan 2002
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    Location: Adelaide, South Australia

    Leo Lazauskas Senior Member

    They are not distributed over a panel. They are just points.

    A Havelock source is like a Rankine source that automatically satisfies the linearised free-surface boundary condition. There's more about this in the papers you found (with Tuck and Scullen)

    There's no need to do that in ship theory, but it is required in, for example, the Neumann-Kelvin problem.

    The slowness of zgreen is mainly due to the fact that the wave elevations are calculated at tens of thousands of points, and no advantage is taken of lateral symmetry.

    It can model a variety of effects at the surface, depending on how many z-derivatives are involved in the free-surface boundary condition. zgreen uses a method involving two z-derivatives to simulate viscous wave-damping at the surface. Other codes I have use three z-derivatives (and a thickness) to simulate the effect of, say, a thin layer of ice slush on the surface.

    Other enhancements include surface tension and the elasticity of the boundary layer on the free-surface.

    Leo.
     
  2. BYDE
    Joined: Mar 2011
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    BYDE Junior Member

    Ok, all clear. Thanks for the explanations!
    Best Regards
     
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  3. Leo Lazauskas
    Joined: Jan 2002
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    Location: Adelaide, South Australia

    Leo Lazauskas Senior Member

    My pleasure.
    And welcome to boatdesign.net, by the way!
     

  4. BYDE
    Joined: Mar 2011
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    Location: Italy-China

    BYDE Junior Member

    Thanks Leo!
    I'm actually using the forum since several years (mainly in lurker mode though), but then I forgot login-info, changed email address, etc... so I decided to just open a new account to make it simple
     
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