Periodic Boundary Condition in EDEM Fluent coupling

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

Hello everybody,
I am simulating a tube with particles by Fluent-EDEM coupling.
Both of the program works well individually.
When I coupled them and used periodic boundary condition, the particles enter in both side of the tube!(inlet and outlet).( the screenshot has been attached).
I selected the periodic direction correctly (Y direction).
Could you please guide me what's the problem?

Regards,
Fatemehimage

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Best Answer

  • Stephen Cole
    Stephen Cole
    Altair Employee
    edited June 2022 Answer ✓

    Hi Fatemeh,

     

    It looks like there might be some instability in the coupled simulation. I would recommend running at a lower time-step ratio between EDEM and Fluent (lower fluent time-step) to see if this improves stability.

     

    Otherwise ramping up the initial velocity of the fluid and starting from a lower creation rate of particles may help to ensure stability of the model at the start.

    Regards

    Stephen

Answers

  • Stephen Cole
    Stephen Cole
    Altair Employee
    edited June 2022 Answer ✓

    Hi Fatemeh,

     

    It looks like there might be some instability in the coupled simulation. I would recommend running at a lower time-step ratio between EDEM and Fluent (lower fluent time-step) to see if this improves stability.

     

    Otherwise ramping up the initial velocity of the fluid and starting from a lower creation rate of particles may help to ensure stability of the model at the start.

    Regards

    Stephen

  • RWood
    RWood
    Altair Employee
    edited June 2022

    Hi,

    I would move the particles away from inlet or run the simulation for a few timesteps first so the flow is well developed.

    My hunch is that you have reversed flow at the inlet or outlet, which is not uncommon in Fluent, which is then pulling particles in the wrong direction initially and leading to them appearing in the other side due to the boundary condition.

    Cheers,

    Richard

  • Fatemeh Hosseini_22198
    Fatemeh Hosseini_22198 Altair Community Member
    edited June 2022
    Stephen Cole_21117 said:

    Hi Fatemeh,

     

    It looks like there might be some instability in the coupled simulation. I would recommend running at a lower time-step ratio between EDEM and Fluent (lower fluent time-step) to see if this improves stability.

     

    Otherwise ramping up the initial velocity of the fluid and starting from a lower creation rate of particles may help to ensure stability of the model at the start.

    Regards

    Stephen

    Many Thanks Stephane. It works.

    Just for the people who may have this problem:

    1. The fluid time step is reduced from 2e-5 to 1e-5.

    2.The initial fluid velocity is increased from 0 to 2 m/s.

    3. The particle rate is reduced from 600000 particle/s to 200000 particle/s.

    Regards

    Fatemeh

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