FreeShip + Michlet for Speed Prediction

Discussion in 'Software' started by navalarchitect, Apr 16, 2013.

  1. navalarchitect
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    navalarchitect Junior Member

    I'm planning to use FreeShip and Michlet to make this catamaran but I'm not sure if it can be modelled in FreeShip and Michlet can give a reliable speed. Any advice?
    [​IMG]
     
  2. Leo Lazauskas
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    Leo Lazauskas Senior Member

    Unless L/B is high Michlet won't give very accurate results.
    I use another program (Flotilla) to calculate the drag of
    this type of vessel when there is an air cushion between the
    hulls. In that case there is a big difference in the wetted
    areas of the inside and outside portions.
     
  3. navalarchitect
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    navalarchitect Junior Member

    Is Flotilla free?
    I have offsets already for this catamaran but my problem is the hull is not symmetrical. How do I input this to Michlet? In every station the hull of the catamaran has different offset on left and right side. In Michlet, you can only input the half side of the hull and it will mirror it on the other side. What is the correct way to do this?
     
  4. Leo Lazauskas
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    Leo Lazauskas Senior Member

    No, the version of Flotilla that handles asymmetric hulls is not free.
    Michlet cannot handle asymmetric hulls.

    Good luck!
     
  5. navalarchitect
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    navalarchitect Junior Member

    what could be the best software to use to model this non-symmetrical local hull and the software to predict the speed and resistance?
     
  6. Ad Hoc
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    Ad Hoc Naval Architect

    The answer is given above:

    But since you have to pay for this, one assumes you mean the best for free?

    And that is a different question from 'what is the best', since the best, as always, costs money. No such thing as a free lunch...
     
  7. tomas
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    tomas Senior Member

    Ad Hoc always spoils the party by bringing reality into the discussion.

    So annoying...
     
    1 person likes this.
  8. Leo Lazauskas
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    Leo Lazauskas Senior Member

    You could try using OpenFoam which is free.
    http://www.openfoam.com/

    Be aware though, it might not be able to handle some aspects of the fluid
    flow problem as well as some other free programs. As AdHoc suggested, with
    free programs you pay your money and you take your chances. ;)

    The attached plot (from a 2012 thesis by E. Colley) is a comparison of the
    far-field wave pattern of a monohull in finite depth water predicted by Michlet
    and OpenFoam. Michlet took a couple of minutes; OpenFoam took 10 hours
    to produce the "wave pattern".
     

    Attached Files:

  9. quequen
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    quequen Senior Member

    Was this image included in the "humor" addendum of that thesis? :p
     

  10. daiquiri
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    daiquiri Engineering and Design

    LOL! I could have made that cyan rectangle at the bottom in less than a minute. Hope the poor guy didn't have to pay for that CFD service. :p ;)
     
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