Planing hull hydrodyamics validation

Discussion in 'Hydrodynamics and Aerodynamics' started by Mike Graham, Jul 26, 2013.

  1. Mike Graham
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    Mike Graham Junior Member

    I can find various papers describing validation cases for resistance, sinkage and trim, and even other hydrodynamic results for planing hulls, but at first glance I can't find any where the geometry is provided, like for some traditional displacement hull validation cases.

    Thornhill et al.'s 2001 conference paper "Planing Hull Model Tests for CFD Validation" provides a section cut for the after 60% of the vessel, which is probably sufficient for reconstruction given the high running trim of the hull at the test speed, but it would be very nice to start with all things equal to the original case.

    Does anyone know which validation cases are the best to use? Does anyone know where to get geometry files for documented validation cases?
     
  2. baeckmo
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    baeckmo Hydrodynamics

    Scientific reports on resistance et c. generally describe the stations of the hull in question; that's part of the issue. So if you come across a text where this is not shown, be sceptic at least.

    There are a number of publications where you find planing hull series data, but they represent a variety of model sizes and speeds, making scaling a bit of a nuisance. Search for "Series 62" and "NPL" for instance. Some of these shapes have been built in sizes from model up to full scale. And wait for our members (Ad Hoc and Leo L for instance) to chime in.....
     
  3. Erwan
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    Erwan Senior Member

    Regarding semi-displact or semi-planing or planing hulls, Most of the workpapers I could find use "prismatic hull" for tank tests.

    Regards

    EK
     
  4. Mike Graham
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    Mike Graham Junior Member

    What I was saying was that the case I had mentioned provided only one section cut. The hull appeared to be prismatic for the relevant part of its length, but a full lines plan was not shown and it wasn't described explicitly.

    Because I'm looking for cases to validate software, rather than use model test data directly, scaling shouldn't be too much of an issue for the direct task.

    Thanks for the leads.
     
  5. Leo Lazauskas
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    Leo Lazauskas Senior Member

    Search for papers by W. Vorus from the Uni of New Orleans, as well as his
    then student B. Taravella. Bill worked on a planing model and showed the
    offsets of vessels he used in the papers.

    Good luck!
    Leo.
     
  6. Mikko Brummer
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    Mikko Brummer Senior Member

    I've used the Thornhill model - I think the model is described well enough in the paper. I can provide you with the model if you like.
     
  7. Adler
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    Adler Senior Member

    Relevant Info

    Try this.
     
  8. Ad Hoc
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    Ad Hoc Naval Architect

    The Thornhill paper is more of a planing “Landing Craft” than a traditional high speed planing monohull.

    It really depends upon what data is provided by the author and how much raw data they provide to validate their findings/theory. Basically if an author claims XX and YY together and shows the results as being ZZ, in an assumption/theory, at scaled/model size, then the very same must be shown at full scale. If the full scale data is partially given, in that only XX and ZZ are given and within a small %’age of the scaled model, there is some confidence, but if only ZZ (the result) is given as noted by baeckmo be cautious. Being selective in the results that “correlate” from the scale/model to the full scale does not make the paper a good one. What is shown at model scale must be shown at full scale...and peer reviewed too!

    This is why scientist/engineers keep asking what appear to be “dumb” questions or “isn’t that obvious” type of questions. Never assume, ever, find the facts of what is or is not provided, no matter how “dumb” the question may appear. If you don’t ask the right question in the first place, just like you’re doing now, you’ll never get the whole truth/data and thus not know if the theory/assumption is valid or not.

    As a starter on planing hulls, you may find the attached of some use. It is a regression analysis of several hull forms, with their lines plan given, for reference.
     

    Attached Files:

  9. lava12005
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    lava12005 Junior Member

    What about Fridsma 1969?
    "A systematic study of the rough-water performance of planing boats"
    Both calm and rough water data is provided there.
    It provides you with the geometry description.

    As for me, I am looking forward to a stepped hull. There's a scanty published result in this area, or maybe its me that cannot find it. So does anyone have any idea regarding this?

    There is one stepped hull tow test by William R. Garland "Stepped Planing Hull Investigation" where the lines is given. But I am not sure regarding the distance between each station.
     

  10. Olav
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    Olav naval architect

    lava12005,

    hope you don't mind I cite myself: *click*
     
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