How to Generate Spherical Particles in EDEM by Scaling to Specific Volume Values?

GuaDong

Dear EDEM users and team members,

I’ve run into a technical question and hope to get some advice from you all. I’d like to know how to generate spherical particles in EDEM that are scaled to specific volume values. For example, I’ve created a spherical particle template with a radius of 10 mm, and I have a CSV file containing a set of unique volume values. Now I need to generate 1000 spherical particles, each scaled according to the corresponding volume value in this CSV file before generation.

I’m wondering if there’s a practical method to achieve this function? I’ve been trying to implement it via the EDEM API Factory, but I’m still working on the specific details. Any guidance or suggestions from those who have experience with this would be greatly appreciated!

Thank you so much for your help in advance.

volume data:

Spherical particle accumulation:

Stephen Cole

Hi GuaDong,

There is no in-built random placement but you can use C++ functions to generate random numbers. You can use the srand function which you typically need to seed:

  srand(time(NULL));//used for random generator

And then generate a number

  double random_number = rand() % 101; //creates random number between 0 and 100

However you can't also access the factory volume so you have to define the limits in global space in which to generate the particles.

The main issue however is there isn't any contact detection, so you have to make sure you don't place particles over the top on one another, or on top of existing geometry. Typically generating the particles in a lattice form and allowing them to drop out of your pre-defined factory area is the best approach.

You can generate the particles incrementally. The factory code is called once per time-step, every time-step.

The code will loop per timestep until additionalParticleRequired = false (or 0). In the snooker tutorial it's got:

// Mark the particle as created

m_numberCreated++;


// We are creating 21 particles, if we've done them all

// then no more are required

additionalParticleRequired = (22 != m_numberCreated);

This means the code will loop at the first time-step, each time it loops it's creating a differnet particle in a different position until it's created 22 particles. When it's created 22 particles it allows the code to move on to the next time-step at which it will hit:

if(time > 1e-7 || m_numberCreated >=22)

{

    particleCreated = false;

    additionalParticleRequired = false;

    return eSuccess;

}

So it enters the factory code again but doesn't create any particles.

You can edit this by specifying at which time you want additionalParticleRequired = true, it requires a series of 'steps' to be set using time and timestep values.

You have to make sure that the code will specify additionalParticleRequired = false at some point in the time-step otherwise it will enter an endless loop and never move forwards.

Regards

Stephen