LIGGGHTS® - User Forum

LIGGGHTS® related topics can be discussed here: discussion about models, installation, feature requests and general discussion

Problem with two or more force fields in a single input script

Submitted by b.saprativ on Wed, 10/29/2014 - 07:04

I am trying to incorporate two separate force fields for two separate block regions in a single input script as I need to giving force in two separate regions

I am using the following script for one block

#zone 1
region spray block -0.0295 0.0555 0.2 0.24 -0.016 0.014 units box
fix push all addforce 0.0 0.1 0.0 region spray

I tried to add the same set of commands for the other for the other zone but its giving error

#zone 2
region spray block -0.01 0.05 0.3 0.4 -0.06 0.01 units box
fix push all addforce 0.0 0.1 0.0 region spray

No rotation of particles

Submitted by JoshuaP on Tue, 10/28/2014 - 14:11

Hi,

I have 6 particles rotating with the same angular velocity. The rotation is caused by a torque, set by fix addtorque.
The problem is that i cant get the rotational speed by compute property/atom and also in paraview it is shown that the aprticles have no angular velocity but I can see them spinning in paraview.

fix integr all nve/sphere

where is the problem?

m.fatahi's picture
Submitted by m.fatahi on Sun, 10/26/2014 - 11:53

dear all
I want to simulate separation of heavy and light particles in Knelson concentrator using DEM by LIGGGHTS 3.0.1
this concentrator works with mixture of particles and water but here I ignore the water. heavy and light mineral particles are separated based on differences in gravity and centrifugal forces while the concentrator rotates very fast.
there are some problems I encounter during my simulations:
1) I can not insert particles with specific features like size, density, percent ... uniformly inside the concentrator (look at the input attached file) ?

Granular poiseuille flow.

Submitted by ACHAL MAHAJAN on Fri, 10/24/2014 - 05:29

I have recently started using lammps and am trying to simulate granular poiseuille flow using the LIGGGHTS. Now I want to use gran/hooke as pair_style but it showed me the following error on compilation "Illegal fix property/global command, not enough arguments (fix_property_global.cpp:50)", though I have used all the fixes for the gran/hooke pairt_style. including the coefficient of restitution, young's modulus, poisson's Ratio ,characteristic velocity and coefficient of friction.

reason for uncongergable simulations

Submitted by ZYan on Thu, 10/09/2014 - 11:32

Hi Christoph, Hi LIGGGGHTSers,
Rencently, i am working on simulations of stirring a peller (steel) in a vassel with particles (radii =1 mm, glass beans ). The simulation behave strangely, withparticles flowing everywhere out of control (cf. attached figure: bad_normal_e). The properties are given at the bottom.

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