Michlet multihulls - drag on individual hulls?

Discussion in 'Software' started by tom717, Jun 23, 2014.

  1. tom717
    Joined: Jun 2014
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    tom717 New Member

    Hi,

    When doing multihull analysis, can you see the drag resistance on each hull including the interference effects?

    I am wanting to see how much drag on each boat for various kayak fleet formations.

    Regards,
    Tom
     
  2. Leo Lazauskas
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    Leo Lazauskas Senior Member

    Yes you can.
     
  3. tom717
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    tom717 New Member

    The Resistance menu seems to show individual hull resistance WITHOUT interference, or collective resistance WITH interference.

    How do I show individual hull resistance with interference?
     
  4. Leo Lazauskas
    Joined: Jan 2002
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    Leo Lazauskas Senior Member

    Sorry, I misunderstood your first question.
    You can't show the individual hulls with interference.
     
  5. tom717
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    tom717 New Member

    Thanks for your replies.

    Do you know any software that might do this, or somewhere I might research it?

    See, my club is trying to figure out whether wake riding penalizes the lead boat, and if so how much. We have lot of opinions, but not much solid data!

    Regards,
    Tom
     

  6. Leo Lazauskas
    Joined: Jan 2002
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    Leo Lazauskas Senior Member

    That depends on the distance between the two hulls, but in general the
    lead boat won't suffer much of a penalty.

    The top figure of those on the page
    http://www.cyberiad.net/waketandem.htm
    shows that the boat at the back gains an advantage when the separation
    is 1.5 wavelengths. It also gains if the separation is 2.5, 3.5, ...
    wavelengths. Clearly, the further back it is, the lower the influence
    it can have on the lead boat.

    When the boats are close together, the "near-field" effects also
    interact, so the lead boat can be influenced by the boat behind (or to
    the side of it). See, for example,
    http://www.cyberiad.net/wakeweinblum.htm

    The pressure field around the boat behind can, for example, induce a
    small amount of trim on the lead boat, which could be beneficial or
    detrimental. Again, the distance between the boats is important.

    I have programs that can determine the effects, but I am in the middle
    of other work at the moment. If you know someone who can run OpenFoam
    or other free CFD codes you might get some good quantitative results.

    Good luck!
     
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