Overlapping Particles MDBC?


I have modified the example case as shown in the included file here. Unfortunately I see that the piston overlaps the fluid particles:

I have tried changing coefh, reducing time step, setting Courant = 0.1 etc. but nothing seems to work. Can someone spot my mistake?

These are things I was suggested to do last time I experienced this problem.

Kind regards


  • So I found the problem.

    You have to ensure that the x-coordinate of the boundnormal_plane is at the correct location, in my case as shown in yellow.

    Kind regards

  • Dear all

    The point should be at dp/2 from last position of the boundary.

    In this case, piston with makbound=10 may finsih at x=40, so point should be 40+dp/2

    Hdp may be defined before as Dp/2


  • The option <initialize><boundnormal_plane> was improved in version 5.0.112. The position can now be automatically calculated from boundary particles and normal data using:

    <point auto="true" comment="Point is calculated automatically accoding to normal configuration." />

    Best regards

  • Please note that new version 5.0 will be released in our public repository by mid July


  • Thanks both of you!

    Awesome to hear about the automatic calculation as well, it seems like it is able to accurately select the correct "side" of the object, since it is based on normals. Looking forward to testing it.

    Kind regards

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