Duplicate Id for particle-wall collision.

Fatemeh Hosseini_22198
Fatemeh Hosseini_22198 Altair Community Member
edited December 2022 in Community Q&A

Hello to everyone.
To identify the particles that collide with the wall, I used this command in python:
ID particle=deck.timestep[t].collision.surfGeom.getFirstIds()

There are many duplicate IDs in ID particle , which confuse me.
Since it is in a specified time step, I anticipate that each particle will only collide with the wall once.
I use this command to find the deposition  and this issue has an impact on my code's output.
Could you please guide me in this field?

Regards,
Fatemeh

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Answers

  • Prasad Avilala_20558
    Prasad Avilala_20558
    Altair Employee
    edited December 2022

    Hi Fatemeh,

    Can you please let us know which version of EDEM are you using, also can you please try the below command

    image

     

    Thanks,

    Prasad A

  • RWood
    RWood
    Altair Employee
    edited December 2022

    Hi,

    The IDs correspond to particles and geometry elements, not just geometries. If you have a particle contacting multiple triangular faces of a geometry then you will see multiple values for the first ID but differing values for the second.

    Richard 

  • Fatemeh Hosseini_22198
    Fatemeh Hosseini_22198 Altair Community Member
    edited December 2022

    Hi,

    The IDs correspond to particles and geometry elements, not just geometries. If you have a particle contacting multiple triangular faces of a geometry then you will see multiple values for the first ID but differing values for the second.

    Richard 

    Thanks for your response.

    That makes problem for deposition investigation.

    Is there a way to constrain the code to only save a particle's ID per geometry contact/face while ignoring other faces (e.g. if a particle contacts more than one face)?

  • RWood
    RWood
    Altair Employee
    edited December 2022

    Thanks for your response.

    That makes problem for deposition investigation.

    Is there a way to constrain the code to only save a particle's ID per geometry contact/face while ignoring other faces (e.g. if a particle contacts more than one face)?

    The simplest option would be to just ignore duplicates in your own bit of Python code. Once you get your list of collisions, just ignore any that have a duplicate of the firstID, since in a p-g collision the particle is always the first element. The downside of this approach is that if a particles contacts multiple geometries, not elements, then you would be discarding some data. A more rigorous approach might be to get all the element (or triangle) IDs per geometry and then remove duplicates after taking these into account:

    image

    Richard