Added Mass Matrix in AQWA

Discussion in 'Software' started by mekchu, Sep 22, 2014.

  1. mekchu
    Joined: Jul 2013
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    Location: Korea

    mekchu Junior Member

    Dear AQWA experts,

    In AQWA NAUT, is it impossible to write out the added-mass matrix infomation for each timestep? Because of my coupling problem, I need to access this information. Please give me any suggestion.

    Thank you so much.
     
  2. mekchu
    Joined: Jul 2013
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    Location: Korea

    mekchu Junior Member

    Any suggestion please.

     
  3. jehardiman
    Joined: Aug 2004
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    jehardiman Senior Member

    Because AQWA is a panel anaylsis it is possible to back extract an apparent body added mass for each timestep (see section 4 of the AQWA Theroy Manual). But it must be remembered that the resolved added mass has no real relevence outside the simulation; it is only about that exact quasi-linear simulation timestep and all the previous timesteps (i.e. pre-existing flow) leading up to it.

    What exactly are you trying to do and why do you think you need the added mass? Many years ago I was involved in the development of some software that needed something like what you are asking for (i.e. extreme change in added mass and hydrodynamic damping in a small distance/timespace). After burning up several years and PHd thesis, we were not able to get a useable result because we finaly determined that previous state drove multi-bifurcation paths in the solution. This allowed the grouping of multiple solution/behaviour states, but it was impossible to predict which one would occur.
     

  4. mekchu
    Joined: Jul 2013
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    Location: Korea

    mekchu Junior Member

    Hi Jehardiman,

    Thank you for your response. I am happy to hear that you were also interested in this problem many years ago. That means you have much more experience on it. Could you tell me how to write out added-mass matrix during unsteady simulation using AQWA-NAUT?
    As I know, added-mass matrix can been obtained from AQWA-LINE for each frequency. Since the convolution method is used, this matrix is made again. I would like to know this matrix in AQWA-NAUT.

    I looking forward to hearing from you.
     
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