Learning Forum

[yujin han]

I'm using Rocky DEM. When I set a garlic clove as a custom particle, no matter how much I increase the volume fill weight (as shown below), the expected number of particles is calculated correctly, but in the actual shape, only 3 particles are generated or a ridiculously small number of particles compared to what I expected are generated. How can I resolve this issue?

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[Lucas Bertollo Baggio]

Hello Yujin,

 

You can start by checking the Volumetric Inlet | Gap Scale Factor, that increases gaps between particles for the surge. You can also check your Particle Orientation and Size to be sure that it fits inside the define volume.

Other than that, you can:

• use a Particle Custom Inlet (.csv) to define exactly how many particles you want in the coordinates you want (as done in Tutorial 22)
• inject by a Particle Inlet until you have the number of particles you want and save the project for restart (as done in Tutorial 14)

Besides the tutorials, also reach the Rocky User Manual to learn more about these features.

 

kinds regards,

Lucas

[Lucas Kostetzer]

Hello Yujin,
the problem is the combination of volume fill and real shapes. Here Rocky can not initilize a packed condtion, but rather spaced only. With spheres we can get very dense packed volumes filled. 
The algorithm will create particles spaced as a virtual sphere around the real shape, this means very far from what we would like to.

You could try two ideas:

1) avoid volume fill and fill a volume in a calculation with an normal inlet.  (easier but can take time)

2) use the volume fill with a reduced size particle (real shape) like 1/10. And activate the volume change module (can be found in the installation files) to increase the particles during the run. 

The volume increase still need calculation time and some try and error of how fast you can do it to avoid instabilities. 

Best regards
Lucas