Dropping a Floating body at a particular time

Hi guys,

I am trying to do drop test simulation on a floating body. For that I am using the example 11: Floating with a small change. I want to drop the floating body at a particular second (after the waves are generated) and not at the time = 0s.

But in the simulation output, it is said that the motion cannot be prescribed to the floating body. Because of that, I cannot prescribe motion of the floating body (here I want it to be above the water surface for few seconds).

Can anyone help how to simulate this case?


  • Yes, you can. Indirectly, since you are able to control this parameter:

    So just write how long before a floating in your simulation may move. Unfortunately you can't specify different floatings to fall at different timesteps, but this should be fine for your case. If you need this in the future, try making a suggestion to the devs.

    Kind regards
  • Got it. Thanks a lot.
    And also to calculate the pressure on the floating body should I have to put the pressure gauge at 1.5 h away from the floating body.
  • edited February 7
    No problem, and yes, because of the boundary condition applied in version 4.2 of DualSPHysics to get a correct result simulation wise, it to place the probe 1.5h away from the border / floating body. Remember that if your floating body moves, your point has to move as well, depending on the movement. Else just find one specific frame and extract the pressure from that.

    Kind regards
  • Got it. I am currently moving the pressure point with the floating body. I was getting unphysical results when I put the pressure point less than 1.5 h from the floating.

    Thanks for clarification
  • Hello,
    How do you move the pressure point/probe with the floating body?
  • @circles you are posting in a fairly old thread, which makes it a bit harder for people to help out. To answer your question, maybe it is possible using the new gauge system in V4.4 of DualSPHysics - I have no experience with it, but maybe some of the examples can help out.

    Kind regards
  • I'll dig into it. Thank you!
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