Coupling of fluent and EDEM

miaomi

Hi,

I use Fluent and EDEM for coupling calculation. Fluent uses 1e-05 time step, EDEM uses 1e-07 time step, and particles can appear vortices; but, Fluent uses 1e-07 time step, EDEM uses 1e-09, the particles cannot form vortices. The two time steps of fluent for flow field are similar. I don't understand. I hope EDEM can also calculate the particle vortex with 1e-09 time step.

time step, and particles have no vortices.

Stephen Cole

Hi, I'm unsure why you would see a difference in results in this case but just to check, why did you reduce the time-step for both EDEM and Fluent?

In the case where you reduce the Fluent time-step it would be interesting to see the results if you keep the EDEM time-step fixed so it matches the Fluent time-step.

It might be that the lower time-step simulation is more stable, and that this is the accurate result. There may be an inertial affect of the particles picking up the flow field which is captured better with lower-time steps in this case

Regards

Stephen

miaomi

Thanks, my results may be questionable.

Now, I have a new problem with fluent and an appearance that -1 particles could not be located in Fluent. -1 particles could not be located in Fluent, so how do we solve this?

Stephen Cole

The 'particles could not be located in fluent' error is usually to do with the particle definition.

In EDEM if we create a particle type and use this in a simulation it gets saved to the file, however if you then change this particle type in the EDEM Creator (for example changing from a 2 sphere to 3 sphere particle or changing the size or size distribution) then EDEM actually creates a copy of the old particle type that you don't see, and updates the existing particle. This causes problems with Fluent as it can't recognise these.

Best way to resolve this is typically to re-create the simulation file to avoid having these 'ghost' particle types stored.

Regards

Stephen

miaomi

But I didn't change the particle type, I just created three particle factories to produce three particles.