How fix the gap between fluid particles and boundary?

edited July 2017 in DualSPHysics_v4.0
Hi all,

Am working on an spillway 3D model, and when i check the results on paraview a gap appears between the edges and the fluid particles, generating unwanted errors, it seems that this gap appears when the fluid gets faster, specially downstream of the spillway

you can see the image of an outline in this link:
https://ibb.co/hOoeja

how can i fix this gap?
Thanks

Comments

  • Its error of method
    One way only - increase number of particles in model, so decrease dx
  • It is a consequence of using Dynamic Boundary Condition.
    The gap is of the order of h, so varying resolution, dp, you will vary h and you will vary the size of this gap

    Regards
  • thanks for the answers.

    There's a way to change the Boundary Condition on DualSPHysics?
  • According to the "News" section of this site, DualSPHysics v4.2 will have:
    "New BCs (LUST, Integral, Ghost particles)."

    ...but for now (v4.0), the Dynamic Boundary Condition is what we have to work with. If your domain isn't too large and you have a GPU with a healthy amount of RAM, then decreasing dp is a good way to mitigate the gap between boundaries and fluid. You'll also notice that the gap between isosurface (Surface_****.vtk) and boundary objects is larger than the gap between PartFluid and boundary objects.
  • Obviusly you can implement a different BC in the source code
    Regards
  • It is possible use periodic.
    For example for DamBreak use

    boxfill>bottom | left | right

    instead

    boxfill>bottom | left | right | front | back

    for Bound Box mk=0

    and

    parameter key="YPeriodicIncZ" value="0.0" comment="Increase of Z with periodic BC" units_comment="metres (m)" />
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