LIGGGHTS® - User Forum

Hello,

Stream of particles are being injected continuously from inlet and they leave the domain through outlet.
I would like to account for all the particles in the domain and even particles which left the domain. (count the particles and save their respective properties such as velocity,density etc.)
Is there a way wherein I can account for the lost particles also and write everything in a file?
I want to plot the average velocity of all the particles in the domain and even lost particles too.

Thank you.

Dear users,

i was suprised when i found in the log file the other time accounts for 68% of the loop time. What is the reason?
How can i do smartly to speed up the simulations?

...
Pair time (%) = 7.30157e-05 (1.02045)
Neigh time (%) = 0.00126994 (17.7483)
Comm time (%) = 0.000835061 (11.6706)
Outpt time (%) = 9.60827e-05 (1.34283)
Other time (%) = 0.00488114 (68.2178)
.....

Cheers,
Zyan

Hi,

I have been trying to install LIGGGHTS 3.1 on Ubuntu 14.04. I have downloaded the latest version and then used the following commands:
make clean-all
make fedora

It works for awhile but then I get the following error:
make[1]: *** No rule to make target `../../lib/gpu/Makefile.lammps'. Stop.
make[1]: Leaving directory `/home/LIGGGHTS-PUBLIC-3.1/LIGGGHTS-PUBLIC/src/Obj_serial'
make: *** [serial] Error 2

I've looked through previous comments for this problem and one issue was not having:
# Path to src files

I am performing a LIGGGHTS simulation with spherical particles moving inside of a pipe around an obstruction. The simulation proceeds fine at first, but once the particles collide with the obstruction, they sometimes accelerate (as if the coefficient of restitution were greater than unity). This seems to be a problem with mesh/surface STL wall specification, as I don't get this sort of behaviour when using planes and cylinders as walls.

I'm trying to use a change box command after a read_restart command to change the boundary conditions. My script looks like this (very general):

read_restart file.restart
.
.
.
run 0 <------ this is suggested in the liggghts manual, under error messeges
change_box all boundary f p f
.
.
.

I still get the error messege "boundary command used after simulation box is defined"

is there another way to change the boundary conditions after reading a restart file?

Hi all,

I encountered a segmentation fault when read_restart.
Can anyone help me find the cause?

The read_restart file "width12.pile" was not included in the attachment because of the size limit.

Many thanks,

Su

Hi guys, i have a problem with my simulation, I want to make a packing, the mesh has tets elements.
i don't know what is my problem

Hello,
I never worked with the heattransfer function of Liggghts and have an problem which I'm unable to solve.

There are two partickles types inserted continously. One at (type 1) 500°C and one at (type 2) 20°C.

dt=0.00001 s
fix ftco all property/global thermalConductivity peratomtype 80. 0.038
fix ftca all property/global thermalCapacity peratomtype 449. 1700.

The radius of particletype 1 is 0.5 mm and from type 2 is 0.7 mm.

dn_dump=1000 that means 0.01s

Hi,

I'm trying to use a compute in a variable. I know that a compute doesnt mean that it is calculated, so I want to use fix ave/time for calculation.


compute A thirdgroup reduce max y
fix currentstatus all ave/time 100 1 100 c_A
run 1
variable B equal c_A
print '$B'


this doesnt work. Just when I use the thermo_style it works:

compute A thirdgroup reduce max y
thermo_style custom step atoms ke vol dt etotal c_A
run 1
variable B equal c_A
print '$B'


Hi,

I am developing a numerical ring shear test. For that I am using a rectangular 3D box with a size of 8e-2 * 8e-2 * 4.4e-2 m. I fill this box with ~25.000 particles with sizes of 9.2e-4 to 16.4e-4 m. After settling under gravity I want to compress the probe with a servo wall and a target value of -5e6 Pa (in z direction).

My particles have follwing parameters, following Aigner et al., 2013 "Determing the coefficient of friction by shear tester simulation":