Michlet 9.30 Released

Discussion in 'Software' started by Leo Lazauskas, Mar 13, 2013.

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

    Leo Lazauskas Senior Member

    The previous version (9.20) of Michlet was downloaded over 6000 times
    and attracted 10 donations over the 2 last years. Many thanks for your
    support!

    If you find Michlet useful, please consider making a small (e.g.
    $10 to $100) donation through PayPal on the Michlet page at:
    http://www.cyberiad.net/michlet.htm

    Only minor enhancements have been implemented in version 9.30.

    The main change is to allow the hull to be submerged to a prescribed
    depth. This makes it easier to study the effects of depth on the wave
    resistance and far-field wave patterns of axi-symmetric and other
    submarine-like bodies.

    Three new hull series have been implemented to generate axi-symmetric
    bodies that have been studied over the last 60 years and for which
    experimental results exist in the open literature.

    Summary of Changes
    ------------------

    * Speeds can now be spaced non-uniformly. This makes it easier to
    compare predictions with measurements at the same speed. It also
    means that more speeds can be be used at low Froude numbers where
    the wave resistance curve oscillates rapidly.

    * Corrected type-setting error of mathematical equation describing
    Series 1 offsets in the Michlet manual.

    * Implemented hull submergence depth.

    * Added Series 4: mathematical axi-symmetric bodies.

    * Added Series 58: Gertler's mathematical axi-symmetric hull series.

    * Added Series 5470: mathematical series to generate DARPA SUBOFF
    bare hull.

    INSTALLATION AND REMOVAL
    ------------------------
    After downloading the file, unzip it into a convenient sub-directory.
    To remove the program, just delete the directory. Michlet does not
    change any system files.

    Manuals are in the docs directory. Start with michman.pdf, the Michlet
    manual.

    < superseded by new version at http://www.boatdesign.net/forums/design-software/michlet-9-32-released-50211.html >
     
    Last edited by a moderator: Apr 18, 2014
  2. Remmlinger
    Joined: Jan 2011
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    Location: Germany

    Remmlinger engineer

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

    Leo Lazauskas Senior Member

    Thanks, Uli.
    I'm not sure if the latest change will be of much help to you.
    You can submerge the whole ship, but not individual components
    to different depths. I could have allowed that option in the
    public release, but it would have meant that the Michlet input
    file produced by Delftship would need modification before being
    able to be used by Michlet. One of Michlet's strengths is that
    Delftship produces a valid input file and I didn't want to ruin
    that inter-operability.
     
  4. Remmlinger
    Joined: Jan 2011
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    Location: Germany

    Remmlinger engineer

    At the time when I started the old thread I was only interested to compare Michlet-results with the towing tank experiments of an isolated vertical foil (Kuhn and Scragg). The question was, if this foil (= rudder without hull) is lowered and the foil is not "wave-piercing" any more, how does this change the wave resistance. I assume Michlet 9.20 will make this simulation now easier.
     
  5. quequen
    Joined: Jul 2009
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    Location: argentina

    quequen Senior Member

    Leo, what is wrong with this file? It comes from Delftship and is not showing any waterlines in the plan view. Michlet shows a wrong LCB also. Edit: it's not wrong, in fact! Now I realize LCB is taken in meters from amiship, positive front.
     

    Attached Files:

  6. quequen
    Joined: Jul 2009
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    Location: argentina

    quequen Senior Member

    How is Submergence related to Fh and Water Depth?
    Seabed Pressure Signature and Fh aren't related to Submergence. They seem to be related to WaterDepth and Fh solely. So changing inmersion of the ship don't change seabed pressures. Is this correct?
     

    Attached Files:

    Last edited: Jul 18, 2013
  7. Leo Lazauskas
    Joined: Jan 2002
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    Location: Adelaide, South Australia

    Leo Lazauskas Senior Member

    Yes, that is correct.
    Sea-bed pressures are only valid for surface-piercing vessels in public releases
    of Michlet.

    Leo.
     
  8. quequen
    Joined: Jul 2009
    Posts: 369
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    Location: argentina

    quequen Senior Member

    Leo, how is the syntax for this new feature? the 930 manual has no changes on this point:

    7.4 Ship Speed Range
    The next three parameters specify the speeds (in ms-1) at which to calculate the resistance and wave
    elevations, via the minimum speed, Umin, the maximum speed, Umax, and the number of speeds, NU.
    The minimum speed and maximum speed must be decimals. NU must be an integer greater than or equal
    to 2 and less than or equal to 101.
     
  9. Leo Lazauskas
    Joined: Jan 2002
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    Location: Adelaide, South Australia

    Leo Lazauskas Senior Member

    It was described in manuals for people who donated to the project at that
    time. The next version (9.32) is almost ready to release but I'm waiting on
    some donations before spending any more time on it.
     
  10. b1ck0
    Joined: Mar 2010
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    Location: Varna/Hamburg

    b1ck0 Senior Member

    Leo, I am wondering ... is it possible to analyze a drillship (including the moonpool) with this software ?
     
  11. Leo Lazauskas
    Joined: Jan 2002
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    Location: Adelaide, South Australia

    Leo Lazauskas Senior Member

    Probably not.

    For a drill ship wouldn't the moonpool be closed and the vessel stationary when
    drillling?

    I can understand it might be important for vessels that lay cables, i.e. they are moving and the moonpool is open.
    Or am I missing something?
     

  12. b1ck0
    Joined: Mar 2010
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    Location: Varna/Hamburg

    b1ck0 Senior Member

    The moonpool is designed as a permanent recess and normally it's quite big (40m x 12m), because all drilling/lowering activities are done through it. Unfortunately it's not possible to cover the moonpool during transit, so we have another sloshing issues inside. My question was if I should model the moonpool in MICHLET or just to assume that it's missing ? I suspect that the moonpool cannot affect the wave pattern generated by the bow/stern of the vessel, but I would be happy if you can give your opinion also.

    P.S:
    Let me summarize:
    1) The moonpool adds resistance to the overall picture. Check added resistance of moonpools (piston and sloshing modes)
    2) Is the moonpool affecting the overall wave pattern generated by the ship ?
     
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