Fluid particle out and its impact on pressure result

Dear Admins and DualSPHysics Users,

I created a 3D simulation of irregular wave interacting with a fixed structure based on the Case Irregular wave Generation. As processing the program, a number of particles had been excluded, however, not by out of density range. The run.txt only reported that "Fluid particle out"...........44.
Can you explain to me: in my 3D simulation, there was 170889 particles if 44 particles were excluded, would it have impact on the pressure result? The result was acceptable or not? And how much particles can be excluded without any impact on result?
Thank you for your help.

Regard,
Hoa X. Nguyen

Comments

  • We have received your email with the case so we will try to check it these days and give you a response soon.

    Regards
  • Dear Mr Alex,

    Thank you so much for your kind response. I received the email, I changed the .xml and run this again. Thank you and wish you all the best.

    Best regards,
  • Dear Dr. Alex,

    Thank admins and you for your kind support. I run the simulation and there are 72 particles out. Could you explain about the particles out? Does it have any impact on the pressure surface of obstacle?

    For example, run.txt
    [Simulation finished 30-05-2017 21:35:28]
    Particles of simulation (initial): 306705
    DTs adjusted to DtMin............: 0
    Excluded particles...............: 72
    Total Runtime....................: 266720.937500 sec.
    Simulation Runtime...............: 266701.937500 sec.
    Time per second of simulation....: 26669.996094 sec.
    Steps per second.................: 0.153433
    Steps of simulation..............: 40921
    PART files.......................: 501
    Maximum number of particles......: 334999
    Maximum number of cells..........: 9792
    CPU Memory.......................: 67054924 (63.95 MB)
  • 72 particles of 306705 should not have a big impact ...
    any problem, please send to us an email

    Regards
  • samsam
    edited July 2017
    Dear Admins/Users,

    I also created a 3D regular wave tank by simply modifying the CaseWavesReg xml file as follows:

    definition dp="0.02" units_comment="metres (m)"
    pointmin x="-1" y="0.1" z="-1"
    pointmax x="8" y="1.9" z="1"
    definition

    Discussing with HoaXNguyen, I shortened the y limits as shown in the codes but it did not work. In my case, almost 25% particles are leaking and most of them are at the boundary edges of Y-direction. Can any one tell me what am I missing here? How can I prevent the particle leaks?

    Thanks.
  • I am just beginner in SPH so we can share.
    1, You still have boundary in Y-direction because you created beach shape. You can check the geometry by using the geometry check in User guide.
    2, In my simulation, I create one more boundary in rectangular shape to avoid leaking, it does not work perfectly, there are 23 particles out but it stay inside the second boundary layer. If you create the second boundary like me, the reult.txt will not show any leaked particles, you need to check the simulation to find where they come out of domain.
    3, . What does this line mean? -> In Userguide, this is the seed point to create the fluid.
    Hope this help.
  • Thanks HoaXNguyen. Problem is temporarily solved. I still have few excluded particles, but it's way better than my previous simulation.
  • Hi HoaXNguyen,

    I was able to complete a simulation with "zero" excluded particle. I think an appropriate resolution of the fluid particles can prevent the leaks. I used a dp of ~H/10 and got no leaked particles out of my ~1.4 million fluid particles. And I did not use any secondary boundary layer that you suggested. The only cons is it takes a longer period of time to finish the run.

    Regards
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