Prediction of non-linear roll damping

Discussion in 'Software' started by CWTeebs, Mar 26, 2012.

  1. CWTeebs
    Joined: Apr 2011
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    CWTeebs AnomalyGenerator

    Hi everyone,

    Does anyone know of any software that helps to predict non-linear roll damping?

    Thanks.

    CWTeebs
     
  2. Leo Lazauskas
    Joined: Jan 2002
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    Leo Lazauskas Senior Member

    There are probably many others, but the source code is available in the public domain version of the Ship Motion Program (SMP).
     
  3. CWTeebs
    Joined: Apr 2011
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    Location: Maine

    CWTeebs AnomalyGenerator

    Thanks for the reply Mr. Lazauskas.
     
  4. CWTeebs
    Joined: Apr 2011
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    CWTeebs AnomalyGenerator

    I found and built the following source, it's from Ikeda's method, last updated in 2009 but the paper it's written from goes back to at least 1981. Like you said, there's probably many others.

    I posted what I've found (somebody else may find this useful).

    Note: the zip contains the compiled executable of the non linear roll damping program, which outputs everything in non-dimensional form.

    I renamed the source to NLRD.txt (from NLRD.f) so I could posted it separate from the executable. I got it to compile in Visual Studio 2008, with Intel Visual Fortran version 11.1.3469.2008.

    It works, in the sense that I managed to get it to write results based on reasonable inputs.
     

    Attached Files:

  5. CWTeebs
    Joined: Apr 2011
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    Location: Maine

    CWTeebs AnomalyGenerator

    I found a novel way of implementing this in AQWA without having to linearize the roll response to a given spectrum by creating a morison element at the turn of the bilge that generates the same viscous drag according to the morison drag equation, then using the "LDRG" (Linearize Drag) in AQWA-LINE Deck 7 with the input pierson moskowitz spectrum.
     
  6. Gary Brown
    Joined: Mar 2012
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    Gary Brown Junior Member

    1 person likes this.

  7. CWTeebs
    Joined: Apr 2011
    Posts: 232
    Likes: 15, Points: 0, Legacy Rep: 171
    Location: Maine

    CWTeebs AnomalyGenerator

    Thanks Gary, that looks quite useful.
     
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