Flotilla 6.1 Released

Discussion in 'Software' started by Leo Lazauskas, Feb 27, 2014.

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

    Leo Lazauskas Senior Member

    This free (64-bit Windows) version of Flotilla is an enhanced thin-
    ship code that estimates the total resistance, squat and wave
    patterns of monohulls.

    The program is not suitable for many classes of hulls. It cannot
    handle planing hulls, or stubby vessels like tugboats and yachts.
    However, it provides acceptable predictions for fine hulls with L/B
    as low as 5 when the hull has a transom stern and for Froude numbers
    greater than about 0.35.

    Latest features and updated reports can be found at:
    www.cyberiad.net/flotilla/flotilla.htm

    INSTRUCTIONS
    To install the program, uncompress the zip file into a suitable
    directory. To uninstall, just delete the entire sub-directory.

    The 44 page manual is in the "doc" sub-directory. That directory
    also contains reports that compare predictions with experiments for
    several systematic hull series, such as AMECRC, NPL, Nova-I,
    Series 64 and Doctor's "Lego" Series.

    Batch files and instructions on how to run the validations are
    included as examples in the manual.

    A program to produce wave pattern graphics is also included.

    DONATIONS
    If you like the program you can make a small donation using PayPal
    on the Monohull web page:
    www.cyberiad.net/flotilla/flotilla_mono.htm

    < newer version now available at http://www.boatdesign.net/forums/design-software/flotilla-6-2-released-50116.html >
     
    Last edited by a moderator: Apr 8, 2014
    1 person likes this.
  2. Leo Lazauskas
    Joined: Jan 2002
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    Location: Adelaide, South Australia

    Leo Lazauskas Senior Member

    I have tested Flotilla on several computers, but it would be helpful
    if somebody could run one quick example.

    After downloading and unzipping the file into a convenient directory,
    run the monoexwp.bat file by double-clicking on the icon in the
    flotilla directory.

    The program will grind away for about 35 seconds (calculating wave
    elevations at about 60,000 points). When it has finished, you should
    see a wave pattern like that below. Press the Esc key to exit.
    The elapsed (wall clock) time is displayed in the console window.

    First person to run it gets a free copy!
     

    Attached Files:

  3. mick_allen
    Joined: Dec 2005
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    Location: vancouver, b.c.

    mick_allen -

    Hi leo,
    According to the command window the time was = .34787E+02 seconds (wall clock)

    [but I'm not sure what type of file the waveplot is to attach it- this is just a screenshot]
    -mick
     

    Attached Files:

    1 person likes this.
  4. Leo Lazauskas
    Joined: Jan 2002
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    Location: Adelaide, South Australia

    Leo Lazauskas Senior Member

    Thanks, Mick!
    The output file from Flotilla is a .pcx file that is stored in the out sub-directory.
    I use free 3rd party programs (like IrfanView) to convert it to other formats.
     
  5. daiquiri
    Joined: May 2004
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    Location: Italy (Garda Lake) and Croatia (Istria)

    daiquiri Engineering and Design

    Lao, that looks like one powerful software! I haven't tested it yet, but I have read the reports in the "doc" folder, and it is incredible how close the predicted curves match the experimental points (or is it vice-versa? :p ) up to Fr=1.0. In particular, I am very surprised and even somewhat puzzled by the accuracy of the resistance prediction for the Nova hull, which is not really a thin ship and plus has a wet transom too... All in all, amazing work indeed!!

    But I'll tell that it really makes me red-hot angry to see that you are fine by just asking for a voluntary donation, while there are countless research papers online which use your software for analysis and which can be read only after a payment of $30-$50 fee to various Springer.com, Wiley.com and similar sites. I know I have already touched this issue in the past, but it just keeps making me feel angry that those folks use your shareware software for making profit. I would even feel better not being able to afford it, at the same time knowing that THEY had to pay you a couple of thousands for using it...

    Well, sorry for this rant. :eek: Now off with trying it... :)

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

    Leo Lazauskas Senior Member

    Thanks for the red-hot rant, Slavi!

    There are a few reasons for the good agreement for the stubby hulls
    like the NOVA-I.

    First, the presence of a transom stern means that the longitudinal
    hull slope is much smaller than if the hull ended in a pointed, or
    cruiser stern. That gets around some of the difficulties with the
    hull not being classically "thin". Apart from that, the hull has
    a fairly fine entrance. I wouldn't expect good agreement if the
    block coefficient was large so that the hull slopes were large at
    the bow: in that case Flotilla would do poorly, whether the hull
    had a transom or not.

    Secondly, as I mentioned in the report for the NOVA-I, I suspect that
    those aren't true measured results: Robards seems to have used some
    form of fit due to Mercier et al. I would need to dig into the paper
    by Latiharju et al to find out what they did.

    Finally, I (with E.O Tuck's help several years ago) came up with a
    fairly good alternative to the "fictitious hollow" method used by
    Molland et al and Doctors. I don't want to give too much away, but it
    is based on the behaviour of transom flows at infinite speeds, and
    some work on semi-infinite hulls. In short, it separates the flow into
    regions directly behind the transom, and those outside of the transom
    hollow. If waves break and crash inside the region behind the stern,
    the effects will hardly be measurable even a short distance away from
    the turbulent mess. (I guess I should publish one day, but I could't
    afford to view my own paper at Springer or Wiley :p)

    The good agreement for the NPL hulls is also almost too good. However,
    there too the experimental points are not actually measured points
    but fits by Molland et al to their experiments. The actual data points
    would appear far more scattered than shown in my report.

    The Series 64 results are quite good but Don Macpherson (among other
    people) has raised doubts about some of the experiments in an earleir
    thread.

    I was a bit concerned by some of my poor squat predictions until I
    read a recent U.S. Navy report where they showed that even
    sophisticated CFD codes can be out by as much as 30%. Of course, the
    experiments might also be dodgy! (There were very significant
    differences between some towing tanks reported at the last ITTC.)

    Next: Catamarans, with viscous interference between demihulls, and
    SES, with planing splash and much, much more... :)
     
  7. rxcomposite
    Joined: Jan 2005
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    Location: Philippines

    rxcomposite Senior Member

    I second that. Students and Pro's use Leo's work.

    I just read in the net. People who have contributed something good to the society and charges a little money keeps earning long after they are gone.:D
     
  8. Ad Hoc
    Joined: Oct 2008
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    Location: Japan

    Ad Hoc Naval Architect

    I hear you there, ditto.... :eek:
     
  9. patrik111
    Joined: Sep 2003
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    Location: Sweden

    patrik111 Junior Member

    First run

    Leo,

    Elapsed time 0,32948E+2 seconds
    on a
    i5-3360M @ 2,8GHz

    Off to play with this the whole weekend :)

    Kind regards
    Patrik
     
    1 person likes this.
  10. Leo Lazauskas
    Joined: Jan 2002
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    Location: Adelaide, South Australia

    Leo Lazauskas Senior Member

    Remember to use some waterlines above the undisturbed free-surface when
    defining your hulls. Unlike Michlet, Flotilla needs to calculate some quantities
    on the wetted part of the hull.

    I'll also try to release Michlet 9.32 within the next two weeks so that you snow-
    bound types have something to do in your alpine huts. :)
     
    Last edited: Feb 28, 2014
  11. daiquiri
    Joined: May 2004
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    Location: Italy (Garda Lake) and Croatia (Istria)

    daiquiri Engineering and Design

    Frankly, if the company and the wine are the right ones, I can think of much better pastimes in a snow-bound hut. :p
     
  12. philSweet
    Joined: May 2008
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    Location: Beaufort, SC and H'ville, NC

    philSweet Senior Member

    Leo, run took 95 seconds on my clunker Compaq Presario C501.

    Ran into a small glitch. The waveplot window in the above example has buttons that don't work. The window can't be closed. It can be minimized, but no full screen or close button. I used task manager to terminate the process.
     
  13. philSweet
    Joined: May 2008
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    Location: Beaufort, SC and H'ville, NC

    philSweet Senior Member

    Does anyone have a source for gnuplot that isn't sourceforge? Apparently, if you can figure out how to decline all the crap they try to load on your computer, it won't give you the download.

    Nevermind, I have it. I have no idea what to do with it, but I have it.
     
  14. philSweet
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    Location: Beaufort, SC and H'ville, NC

    philSweet Senior Member

    I can't locate any .exe files in the download. I found a reference to a bin directory that I don't have either. Any ideas?
     

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

    Leo Lazauskas Senior Member

    As I wrote in the post, Press the Esc key. :)
     
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