FreeShip + Michlet for Speed Prediction

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

  1. navalarchitect
    Joined: Feb 2008
    Posts: 30
    Likes: 1, Points: 8, Legacy Rep: 26
    Location: anywhere

    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
    Joined: Jan 2002
    Posts: 2,696
    Likes: 151, Points: 63, Legacy Rep: 2229
    Location: Adelaide, South Australia

    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
    Joined: Feb 2008
    Posts: 30
    Likes: 1, Points: 8, Legacy Rep: 26
    Location: anywhere

    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
    Joined: Jan 2002
    Posts: 2,696
    Likes: 151, Points: 63, Legacy Rep: 2229
    Location: Adelaide, South Australia

    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
    Joined: Feb 2008
    Posts: 30
    Likes: 1, Points: 8, Legacy Rep: 26
    Location: anywhere

    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
    Joined: Oct 2008
    Posts: 7,115
    Likes: 1,057, Points: 113, Legacy Rep: 2488
    Location: Japan

    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
    Joined: Nov 2012
    Posts: 281
    Likes: 16, Points: 0, Legacy Rep: 147
    Location: California

    tomas Senior Member

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

    So annoying...
     
    1 person likes this.
  8. Leo Lazauskas
    Joined: Jan 2002
    Posts: 2,696
    Likes: 151, Points: 63, Legacy Rep: 2229
    Location: Adelaide, South Australia

    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
    Joined: Jul 2009
    Posts: 370
    Likes: 15, Points: 28, Legacy Rep: 199
    Location: argentina

    quequen Senior Member

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

  10. daiquiri
    Joined: May 2004
    Posts: 5,373
    Likes: 254, Points: 93, Legacy Rep: 3380
    Location: Italy (Garda Lake) and Croatia (Istria)

    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 ;)
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.