Buoyancy Force

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Comments

  • edited October 2016
    Exactly IMC
    ComputeForces for NO FLOATINGS just calculates forces as summation of ACE (computed with PartVTK) * mass

    Regards
  • Hi
    I have tested the NEW Exec files.
    The target is to compute the vertical force (Fz) applied to a box resting in a fluid.
    The size of the box is 3m*3m.
    Two test were carried out:

    1) relativeweight="1.3"
    * Fz computed by "ComputeFroce" : 1.12*10^5
    * Fz computed by "ACE from PartVTK" : -4.12*10^3

    2) relativeweight="3.0"
    * Fz computed by "ComputeFroce" : 2.6*10^5
    * Fz computed by "ACE from PartVTK" : 1.84*10^3

    I can not understand these numbers.

    The files are attached:

    https://drive.google.com/open?id=0B88w8RZeyGjHdzJ0RTlYX09QU2M

    https://drive.google.com/open?id=0B88w8RZeyGjHZkdYTlN6NGdSX3c
  • If you have received the new ComputeForces now you can compute the buoyant force for floatings while ACE from PartVTK is the summation of buoyancy plus weight!

    Regards
  • I computed these value with the New tools!

    If the ComputeForces, calculates the buoyant force, there is a difference between relativeweight of 1.3 and 3. While the bouyant force is independent of the density!!!
  • Hi Alex
    Have you looked at the problem?

    Regards
  • Dear Alex

    Would you please explain a little more about the confusion?
    4 posts above, it is shown that by changing the relative weight, the buoyant force also changes, which is not OK.

    Regards!
  • Yes, the buoyant force does not change with relative weight.
    The issue now is that ComputeForces for floatings gives you not only the buoyant force but also buoyancy+weight!!! that is why different weight(different relative weight) gives you different results.
    Next release will include new ComputeForces that only computes the buoyant force. When this is released please check it again. We will try to finish a new release soon

    Alex
  • Alex,

    You mentioned, "Next release will include new ComputeForces that only computes the buoyant force". Which release were you talking about? I think the version 4.0 that I am using still computes contact force plus weight for floating objects. Moreover, the force changes dramatically (from +XN to -2XN) as I increase the number of particles which does not make any sense. I emailed this issue to the support team and they stopped helping me after a couple of replies leaving the issue unresolved.

    In summary, this code's ability to compute forces on a floating object is a total mess. It deserves some clarifications.

    Regards.
  • We will try to release the new version with new ComputeForces as soon as possible. Meanwhile, email us and we will provide you with the new version of that code so you can try it and tell us how it works

    Regards
  • Thanks Alex for helping me out on this. I have just sent an email with a subject line "[Buoyancy Force] - ComputeForces Code New Version".

    Regards.
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