Reports of the 26th ITTC

Discussion in 'Hydrodynamics and Aerodynamics' started by Leo Lazauskas, Aug 15, 2011.

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

    Leo Lazauskas Senior Member

    Pre-prints of the reports from the 26th ITTC are now available at:
    http://www.cmeventos.com.br/ittc2011/discussions/list.php
    Many of these reports should be of great interest to those in this forum.
    Each report has a very extensive list of references which will be useful to researchers.

    People should be a little wary of some of the results in the report of The Resistance Committee.

    There seem to be some serious mistakesr on page 13.
    The results look very poor because the wave cuts have been reversed for some data.

    For example, in Figure 32 on page 13, I suspect that results are for some hulls travelling to the left,
    and the others are for the hull going to the right. The curves match quite well if reflected about midships.
    The same problem can also be seen in Figure 36.
    (I have emailed the ITTC about this, but have not heard anything back yet.)

    If anyone here is sufficiently interested, I'd be interested to hear if I am reading those graphs correctly.

    There some other serious issues raised in this report.
    For example, the ITTC received results from 21 towing tanks as part of their Facility Bias Worldwide Campaign.
    Of these, only 12 were in the correct format and of any use. A few towing tanks just sent back the example
    spreadsheets without changing the values in the example!
    I suspect that there were language difficulties in organising this otherwise splendid worldwide research effort.
    Maybe the lesson here is to use a towing tank that speaks the same language as the client.

    These sort of errors and mix-ups show that one should not place 100% faith in towing tank experiments,
    and to be wary of cherry-picking results to support or discredit CFD and other theoretical work.

    Leo.
     
    Last edited: Aug 15, 2011
  2. johnhazel
    Joined: Jun 2008
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    Location: Michigan

    johnhazel Senior Member

    Nice detective work there Leo. It's always good to remember that the fancy guys in their ivory towers are human too.

    These sort of errors seem to run throughout all of science. The area I am familiar with is force calibration of Atomic Force Microscopes. There were many questionable results and methods which were adamantly defended by those who stood to be embarrassed over the silly mistakes that caused the questionable results.

    Be careful though, buffoons in powerful positions can be quite vengeful........
     
  3. Ad Hoc
    Joined: Oct 2008
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    Location: Japan

    Ad Hoc Naval Architect

    Cheers
    I'll have a read of these :)
     

  4. MikeJohns
    Joined: Aug 2004
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    Location: Australia

    MikeJohns Senior Member

    Thanks Leo

    I just looked at the conclusion for the CFD report :)
     
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