how to define packing fraction of particles

Hi,

I am not really sure, what is the packing fraction, but if you mean
porosity, you can "play" with R_{max}/R_{min} range.

Anton

Thank you Anton,
yes, i mean porosity.
Do yo mean I set the minRadius and the maxRadius to different values?
However, even the ratio of max and min radius keeps constant, for example, equals one, that would probably have different porosities, due to the particle arrangement.

In my issue, the radius is 0.2 and i want to set porosity 0.4, how can i do this? thank you very much.

Hi Guo,

The porosity of a RandomBoxPacking can be controlled by changing the ratio of max to min radius. I recommend that you check the max radius constant and change the min radius to achieve a desired porosity. The max radius should be no larger than 0.1 times the smallest linear dimension of your domain. You will need to experiment with the min radius to get a porosity close to 0.4. I would start with a value for min radius around 0.3-0.4 times max radius.

Cheers,

Dion.

Thanks a lot, Dion. But i mean in my case, the radius of all particles is 0.25. and the container is 10(x-direction)*10(z-direction)*5(y-direction). How can i get a porosity to 0.4? The possible way is to control the number of particles, in this case, if the number is 4584. I have no idea how to do this in Esys-particle? Could you help me on this? Many thanks.