frienship-michlet integration

Discussion in 'Software' started by Chris Pap, Jan 29, 2013.

  1. Chris Pap
    Joined: Jan 2013
    Posts: 13
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    Location: Athens, Greece

    Chris Pap Junior Member

    Dear Fellows

    My name is Chris Papandreou and i am a student in the school of naval architecture and marine engineering at NTUA in Greece.My diploma thesis is in ship design and optimisation with Mr A. Papanikolaou.
    I was trying to call michlet from friendship and to create and automatic design engine for optimisation (michlet is awesome for this purpose as it combines valid and quick results),
    but i am facing a problem. In order to find the resistance in michlet user interaction is needed(pressing R,T). I discussed this matter with Mattia Brenner(from friendship) and even Mattia had not a solution. So i want to ask you if there is something that i miss? Perhaps a version of michlet that runs in batch mode or if there is anythng else that i can try to achieve my purpose.
    I want to thank you in advance for your time and assistance.

    Best regards,
    Chris Papandreou
     
  2. Leo Lazauskas
    Joined: Jan 2002
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    Location: Adelaide, South Australia

    Leo Lazauskas Senior Member

    Hi Chris,
    I have not released a free, batch-mode version of Michlet.
    However, I will release Flotilla version 5.0 in the next few weeks. That
    is a text-based program that can be run in batches and it is relatively
    easy to change the input files using other programs you can write yourself.

    Also, if you are just considering monohulls and you don't need estimates of sqaut, Ulimich might be Ok for your project.
    It can be run in batch mode.

    Good luck with your studies!
    Leo.
     
    Last edited: Jan 29, 2013
  3. Chris Pap
    Joined: Jan 2013
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    Location: Athens, Greece

    Chris Pap Junior Member

    friendship-michlet integration

    Dear Leo

    Thank you for your interest and your quick reply.
    Unfortunatelly i am trying to optimise a swath so ulimich cannot help me right now(although i will download it, these things are always usefull).
    I looking forward to run Flotilla then in the next weeks.
    Thank you again, and congatulations about michlet.

    Best regards
    Chris Papandreou
     
  4. Leo Lazauskas
    Joined: Jan 2002
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    Location: Adelaide, South Australia

    Leo Lazauskas Senior Member

    I strongly suggest that you look at this thread:
    http://www.boatdesign.net/forums/hy...sistance-predictions-using-michlet-42258.html

    As you will see, SWATH require some special treatment vis-à-vis form drag.
    In general, you do not need to use any form factors for most thin hulls,
    however:
    (1) SWATH usually have a rounded nose (which violates the thin-ship
    assumption) and
    (2) It is best to use two form factors: one for the strut and another for the
    torpedo-like lower portion.

    These dual form factors are a rough-as-guts way of accounting for (1) and
    possible separation at the intersection of the strut and bulb.

    The 1st post in the thread also contains a short report that compares
    Michlet predictions with towing tests of a model SWATH. The strut and bulb
    are comprised of mathematical shapes, so you should be able to create the
    offsets yourself. One way is to use Michlet's mathematical hull series and
    combine them into a SWATH strut-bulb combination. It's a bit messy, but
    it will actually give very accurate (4 or 5 figure) accuracy for the shapes.
     
  5. DCockey
    Joined: Oct 2009
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    Location: Midcoast Maine

    DCockey Senior Member

    Question for Leo: My understanding is the wave amplitude fields generated in Michlet for a multihull vessel are the same as would be obtained if:
    1) The wave amplitude fields for each hull in isolation were generated independently in Michlet.
    2) Each wave amplitude field was shifted in space to correspond with the position of corresponding hulls in the multihull configuration.
    3) The wave amplitude fields were combined by superposition to obtain the wave amplitude field for the multihull.
    Also, my understanding that calculating wave drag of a multihull requires use of the combined wave amplitude fields due to non-linearity of the wave drag with wave amplitude.
    Is this correct?

    Update: I had previously asked a related question which Leo had answered in post #27 of the thread which Leo referenced above. http://www.boatdesign.net/forums/hy...stance-predictions-using-michlet-42258-2.html
     
    Last edited: Jan 29, 2013

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

    Leo Lazauskas Senior Member

    Yes to all, without the effects of boundary displacement thicknesses and
    without viscous wave damping. Otherwise, there is also a weak Reynolds
    number dependence and an influence from the other hulls in the ensemble.
    In Flotilla there are some other interactions between the demihulls I have
    included that are not in Michlet.
     
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