LIGGGHTS® - User Forum

hi to everyone

can any body tell me is there any command that must be used for different size particles ?

Hi,
I am using liggghts data for a macro-scale simulation, where there is aggregation happening leading to increase in the size of the particles. I want to restart the simulations from the previous state but with the new particle sizes. Is there a way to achieve that. Merely changing the sizes in the new infile leads to an insertion error.

Thank you for your help!

-Chai.

aoa

particle are not mixing like discrete . they move like chunk and do not mix properly ... i m uploading my input file plz help me because i have to submit my work this week. i m uploading a pics and code

#Poly dispersed flow

atom_style sphere
atom_modify map array
boundary f f f
newton off

communicate single vel yes

units si

region cyl cylinder z 0. 0. 0.075 0. 0.320 units box
create_box 2 cyl

neighbor 0.003 bin
neigh_modify delay 0

#Material properties required for new pair styles

Hello,

I want to determine average of velocity square < (Vx^2) > and later average it in a band at different heights in the domain.
I tried to do so in the following way using variable and fix ave/spatial command.

variable gvx equal vx*vx
variable gvy equal vy*vy
variable gvz equal vz*vz
fix gvel all ave/spatial 1 1000 1000 z lower 0.01 v_gvx v_gvy v_gvz file meanv.txt

Hi all,

I have seen the LIGGGHTS v3.x doc about the command 'fix insert/pack'.

For the restriction, it says "The overlapcheck = ‘yes’ option performs an inherently serial operation and will thus not scale well in parallel. For this reason, if you want to generate large systems, you are advised to turn overlapcheck off and let the packing relax afterwards to generate a valid packing.".

What exactly I have to do to let the packing relax afterwards? Thanks.

Regards,
Josh

Hello!

Hello everyone,

I wanted to have the coordination number in my simulation and used the following codes in my simulation:

compute CN all coord/gran
dump cn all local/gran/vtk 100 post/coordnumber*.vtk CN

But it didn't work. Can you see any problem with these 2 lines?
Thanks

In Liggghts, can we set an initial quaternion and update it for a multisphere particle, or hybrid sphere molecule clump?
Same as asphere, can we also output the cumulative quaternion (compare to quaternion at time = 0) of each clump/multisphere?
Such that we can not only track the positions (center of mass) but also the degree of rotation of all clumps.

Greetings,
David

Hi Friends,

Good morning,

I am using a hybrid granular bond/gran model and reading the structure with read_data.
How to solve the error "Incorrect atom format in data file"? The file structure I have is below.

Thank you,
rob1

---
LAMMPS data file via write_data, version Version LIGGGHTS-PUBLIC 3.7.0, compiled 2017-08-14-17:13:57 by XXX, git commit unknown, timestep = 750001

30000 atoms
2 atom types
1549 bonds
1 bond types