particles in channel

Palabos General
#1

Hello,
I want to model non-spherical particles in water flow in square channel.
I am trying to extend the program of “particles in cone” to my desired program but have some questions:

1- Is palabos able to model non-spherical particles?
2- I cannot find information regarding particles density and size and concentration in “particles in cone” program.
3- how can I use square geometry instead of cone without using triangle set?
4- what is the difference between particles modeling in “particles in cone” and “particles in tube” programs?
5-In the program of “external flow around obstacle” particles are also used but it is mentioned that particles are just used for visualization. what does this mean? it means that particles collisions with each other and fluid is not considered?
6- which model is used for particles modeling in “particles in cone”? Ladd, … or etc.
any helpful information regarding particles modeling in palabos in highly appreciated.
Thank you in advance

#2

Hello everyone,

I’m also interested in an answer to the questions 2,5 and 6. Furthermore I would like know when a documentation for particles in Palabos will be made public.

Thank you for your help!

#3

Hello everyone,

I am also interested in an answer to the questions 2,5 and 6 of above. I am trying to model particle sedimentation (following the approach of Ladd), and I would like to know more about how particles (and particle-fluid couplings) are handled in the program “Particles in a cone” (which radius do the particles have? which boundary conditions are applied to the particles? Etc…)

Thank you for your time and help.

Alessio

#4

Hello,

I’ve also started to work on the particles library.

So, I just have some answers on what I’ve understood (but it might be unexact).

Concerning the 5th question, I suppose it is mentionned “just used for visualization”, because the particles are massless particles, which means that the particles are just following the streamlines. Thus, there are indeed no interactions between the fluid and the particles, and between different particles.

Concerning the 6th question, only the gravity and a repuslive force are taken into account for the forces acting on particles in the “particles in cone” program.

If you want to model non-spherical particles, I guess you “just” has to write your own “ParticleInteractionForce” like in the “particles in cone” program, with your own drag force, lift force, etc… :slight_smile:

Finally concerning the 2nd question, the initial concentration can be adjust with “particleProbabilityPerCell”.

Did you find how to adjust the initial veliocity of the particles ? I thought it was during the declaration of the template, but its not working. Like “particleTemplate = new VerletParticle3D<T,DESCRIPTOR>(1, Array<T,3>(0.,5.,0.));”, if I want a speed of 5 in the Y-direction.

Furthermore, I don’t undertsand the values (lattice units ?) of the different forces :
T fluidCompliance = 6.e-5;
Array<T,3> gravity(-3.0e-7, 0., 0.);
T forceAmplitude = 1.e-4;

Mat

#5

Hey Mat fr, thank you for your answer.

I still have a question regarding the “particles in cone” code Do somebody know if the particles are expanded particles with radius/size which also have an influence on the fluid flow? The code uses the Guo off lattice method for curved boundaries, so I assume it could be possible. Or do the code simulate particles points with no expansion?

Kind regards

Palabosfan

#6

Hi Palabosfan,

The particles in the particles in cone example are point particles. Thus, they do not has a radius or size. In turn they do not have an effect on the fluid field.

Kind Regards,

Muaaz

#7

Hallo muaazb,

thank you for your answer!