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EDEM v2025.0: How to Track Collision Dissipation Energies (Negative Particle-Wall Energy Loss)?

User: "Jacob_at_Altair"
Altair Community Member

Description: I am interested in tracking the energy dissipated in collisions due to heat generation / sound / other losses in the context of a system involving multiple particles and a moving geometry mesh boundary. By tracking collisions in EDEM, I have extracted the normal/tangential/total 'Energy Loss' attributes of each collision, which are positive for particle-particle collisions, but they can be negative for particle-wall collisions. I understand that this is because 'Energy Loss' is calculated as the change in particle energy before and after a collision, and the moving mesh boundary can impart energy onto a particle. For those such particle-wall collisions, how could I calculate the energy that is lost to heat / sound / other losses (i.e., dissipation energy)?

I tried using the EDEM Energy Dissipation API posted in this community Q&A, but its outputs (as far as I could tell) lumped the information of all collisions between selected timesteps together to generate summary histograms and total system energy dissipation values. How can I retrieve the dissipation energies corresponding to each collision event that occurs in the simulation, such that the dissipation energies could be associated with the collision ID (and accordingly the coordinates, relative velocity, and involved particles of the collision)?

Product/Topic Name : EDEM v2025.0

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    User: "Renan"
    Altair Employee

    Hi Jacob,

    To get such information from the collisions, you have to use the track collisions option that is available in the simulator. Please note that track collisions is only available in the CPU solver.

    Best regards,

    Renan

    User: "Jacob_at_Altair"
    Altair Community Member
    OP

    Hi Renan,

    I had used the track collisions option, and I was able to output the Energy Loss attribute. However, this attribute gives the particle energy after the collision minus the particle energy before, causing some particle-wall collision Energy Loss values to be negative. I was wondering if there was any way to output the dissipation energy for each collision (as calculated by integrating the dampening forces - not the energy loss attribute) by using the track collisions option.

    Best,
    Jacob

    User: "Renan"
    Altair Employee

    Hi Jacob,

    In EDEM a collision is made of many different contacts. This energy loss model in the community calculates the energy dissipation for every contact, so if you were to save every timestep of your simulation you'd be able to calculate the energy loss of each collision. Keep in mind that this would significantly slow your simulation down.

    Best regards,

    Renan