Interference Factor

Discussion in 'Multihulls' started by navarch_hish, Aug 25, 2006.

  1. navarch_hish
    Joined: Jun 2006
    Posts: 18
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    Location: India

    navarch_hish Junior Member

    I am designing a high speed catamran ferry. 35knots speed..

    I am doing the resistance part of the project and i need data regarding the intereference factors..

    Viscous interference factor
    Wave intereference factor


    Can anyone tell me on what factors these depends on and can somone provide me some graphs from which i can interpolate to find the intereference factors suitbale for my vessel

    My vessel Details
    LOA = 49.4
    Bship= 13.2
    bhull = 3.17
    D = 4.32
    T = 1.72
    CB = .625
    LCB = 6.2% aft of midship

    Give ur comments on my ship
     
    navarch_hish, Aug 25, 2006
    #1
  2. marshmat
    Joined: Apr 2005
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    Location: Ontario

    marshmat Senior Member

    Hi navarch,
    It sounds like this is a school assignment. Do you have any textbooks handy?
    I'm curious as to what you mean by "interference factor". Are you trying to figure out how much drag is due to the interference of the wakes of the two hulls? That's virtually all due to waves... the (viscous) boundary layers of a cat's two hulls don't usually meet each other.
     
    marshmat, Aug 25, 2006
    #2
  3. Tim B
    Joined: Jan 2003
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    Location: Southern England

    Tim B Senior Member

    Have a look at the work by A.F. Molland (et al.) from Southampton University (UK). A lot of tank testing was done and the findings are well presented. This should answer your question.

    Tim B.
     
    Tim B, Aug 26, 2006
    #3

  5. tspeer
    Joined: Feb 2002
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    Location: Port Gamble, Washington, USA

    tspeer Senior Member

    If the hulls are symmetric and carrying no side force, you can compute the wave interference using Michlet.

    For some experimental data on asymmetrical hulls, see
    Papanikolaou, et al, "Hydrodynamic Optimization of Fast-Displacement Catamarans", Twenty-First Symposium on Naval Hydrodynamics (1997), The National Academies Press, http://darwin.nap.edu/books/0309058791/html/697.html.
     
    tspeer, Aug 26, 2006
    #4
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