boundcorrection of v4.3

A question about the new function of boundcorrection of v4.3:
Is the gap between the fluid and the particles was corrected in the boundcorrection of 4.3?

Comments

  • I have tried to run the example of boundcorrection. I found that the gap has been removed between the fluid and boundary. but the boundary must be fixed . If I use the floating . the gap between the fluid and floating is still existed.
  • Dear user

    The boundcorrection is still under development.
    And beta version 4.3 only includes that correction for fixed and moving boundaries with simple geometries, but no for floating rigid objects.
    We will extend and improve this correction for v4.4

    Regards



  • @Alex thanks for your reply and sorry for my email with the same question.
  • no problem
    thanks to you
  • @Alex
    I have a question about the floating . In the xml I use drawmode=full to generate sphere So the sphere is full of granules. And I use drawmode=full to generate a poly (stl) but the poly is empty and only the boundary are granules. So will it have some effection to accurancy calculation?
  • HI, with .stl files gencase only generate particules on surfaces (the drawmode does not matter). Generaly, it will impact your simulation.
    In order to fill your geometry with particule you should use fillbox (see XML_v4.0_GUIDE.pdf page 44)
    Basically, you specify a seed, a reference point and a size of box. Then the program wil instantiate particule from the seed inside the box while the modfill is true (in your case I'd put void)
    bye
  • edited November 15
    @TPouzol
    You mean if I use stl to generate floating, the floating must be filled with particles or the result may be wrong?
    the interaction between fluid and floating is different from boundary?

    Is it relate to the relativeweight.do you think so?
    Regards
  • @Alex @TPouzol
    These days I read the JSphBoundCorr.h and JSphBoundCorr.cpp. But I am confused with these variables:
    //-Configuration parameters.
    TpDirection AutoDir; ///<Direction configuration for automatic definition.
    double AutoDpFactor; ///<Point is calculated starting from bound particles at distance dp*AutoDpFactor.
    tdouble3 LimitPos; ///<Limit between boundary and fluid.
    tdouble3 Direction; ///<Direction to fluid particles.
    tfloat4 Plane; ///<Plane in limit.

    Although there are explanition after the definitons.
    Is AutoDpFactor to remove the gap between fluid and boudnary?
    What is the role of limit between boundary and fluid?

    Is there any papers about the metheod of boundary correctiong recommended ?

    All regards.
  • This is still under development.
    We are now improving and testing the algorithms and then we will produce some journal papers.
    We will let you know when we have more improvements.

    Regards
  • @Alex
    The boundarycorrection can just be used on CPU calculation, and could not be used on GPU now, right?
  • Hi @Alex @TPouzol
    About the boundary correction I see 8 directions in the JSphBoundCorr.h,top/bottom/front/back/left/right/none/defined. So I want to know if the correction can be applied to the complex boundary, like a stl boundary(fixed boundary)?
  • Recenctly I am trying to make boundary correction between floating boundary and fluid to move the gap, so that I can get more accuracy result under low resolution. And the gap between fixed boundary and fluid has been moved successfully in version 4.3. I reference the code JSphBoundCorr.h and JSphBoundCorr.cpp but it is difficult to achieve. So I want to get your idea if it is significant to do this work, and is there any other approaches to improve the accuracy? Because the cost of small dp is so high that we can not accept to simulate some simple cases.
  • I think @Alex answered your question in his first post in this subject.

    "Dear user

    The boundcorrection is still under development.
    And beta version 4.3 only includes that correction for fixed and moving boundaries with simple geometries, but no for floating rigid objects.
    We will extend and improve this correction for v4.4

    Regards"

    Regards
  • @dong what sound of speed are you using in your calculation? Often setting too high a sound of speed will increase simulation times a lot.

    Your sound of speed should be 10 times higher than the highest velocity in your simulation. Ie. if the highest velocity in your simulation is 1, set it to 12 (just to be safe) - don't use the physical correct value of your fluid since the only purpose of sound of speed is to ensure incompressibility according to Tait's equation.

    I hope it helped a bit.

    Kind regards
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