Free decay analysis by AQWA

Discussion in 'Software' started by mekchu, Oct 25, 2013.

  1. mekchu
    Joined: Jul 2013
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    Location: Korea

    mekchu Junior Member

    Hi AQWA's users,

    I am trying to find natural mode of simplify free floating box by AQWA. In order to do that, I am using time domain analysis (i.e., AQWA-NAUT) with given starting condition for each modes. One thing I am confusing my analysis is time response result of sway/surge mode. Time response output of sway/surge modes tends to be neutral pattern while heave mode is convergence response. Basically, those modes should be convergence response due to damping of radiation effect from structure vibration.

    Can anyone help me solve this situation?


    Best regards,
     
  2. musiice
    Joined: Sep 2013
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    musiice Junior Member

    Hi mekchu,

    Could you include more details about your model?

    You can obtain the natural frequencies already in aqwa-librium. Anyway, in aqwa-naut you can verify these are correct.

    Did librium converge? Have you check it?

    In Naut, I assume you are defining a regular wave with the smallest amplitude and long period. If the period matches a natural frequency then you should see resonance for that mode.

    Regards
     
  3. mekchu
    Joined: Jul 2013
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    mekchu Junior Member

    Hi Musiice,

    Thank you for your response.
    Actually, I checked natural frequency in AQWA PER. They are undamped natural frequency. However I want to see damping data from AQWA-NAUT which can be used to check natural frequency as you mentioned.

    Best regards,
     
  4. mekchu
    Joined: Jul 2013
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    Location: Korea

    mekchu Junior Member

    Hi Musiice,

    I used typical example which show in AQWA-NAUT manual. I modified mooring system with different anchor location. This is just test model to understand. I still have same problem as I asked above. Can you give me some advises?

    I attached input file here

    Best regards,
     

    Attached Files:

  5. musiice
    Joined: Sep 2013
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    musiice Junior Member

    Hi mekchu,

    I will take a look later, if you are interested you could send me a private message with a contact address I might have the time to work out an example for you.

    Kind regards
     

  6. UTKARSH RAMAYAN
    Joined: Oct 2012
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    Location: IIT MADRAS

    UTKARSH RAMAYAN Junior Member

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