Hi all,
I'm new to LIGGGHTS and I got some problems when I run the examples in CFD-DEM coupling package. The example is settlingTestMPI.
First of all, I cannot get the cfdemSolverPiso_settlingTestMPI.eps because of the error bellow:
error: load: ../../DEM/post/velocity.txt: inconsistent number of columns near line 171
error: load: unable to extract matrix size from file `../../DEM/post/velocity.txt'
error: called from:
error: settlingVelocity.m at line 41, column 6
Then I checked the velocity.txt file and found that the problem of inconsistent number of columns does exist in line 172 which contains only 3 columns while other lines contain 4 columns. I do not know what cause this problem.
Second problem is about the dump file. I noticed that there is one similar post in this forum, but it does not solve my problem. Pizza.py dump not reading all snapshots. There is 85 snapshots in my simulation, but only 14 snapshots are read by Pizza.py. When I check the dump.liggghts_init file, I found that in some snapshots the format of the data is wrong. The data in one line is not complete. For instance, when the program output this line:
ITEM: ATOMS id type type x y z ix iy iz vx vy vz fx fy fz omegax omegay omegaz radius
the following lines about these data should correspond to the items above. However, there is one or two lines at the end of one snapshot would contain few items, say, there is no data about omegay omegaz radius. What's more, the key word ITEM: TIMESTEP would follow that specific line. I do not know what's wrong with that.
These problems always exist when I try to run simulation with fluid and atoms interaction. However, when it just deals with atoms, everything is ok. I'm not sure if there is a problem with the coupling procedure.
PS: I'm using Ubuntu 10.04 in virtual machine VMware. The system is 64 bits.
Please, anyone can help me about that?
Yours,
Tao
cgoniva | Mon, 05/16/2011 - 08:24
Hi Tao, Probably the
Hi Tao,
Probably the simulation does finishes as it should (crashes) and data is not written correctly?
Please try a different simulation setting.
Cheers,
Chris
Tao | Tue, 05/17/2011 - 12:52
Problem occurs when particles interact with fluid
Hi Chris,
Thank you very much for your reply.
I tried several different simulation settings. However, the same problem occurs when particles interact with fluid. The data in dump file cannot be written correctly. In fact, the program works well when there is no interaction between particles and fluid. I do not know what's going on. I hope you can give me some suggestion on this problem.
Here is one part of the script, that I want to print the velocity to a file velocity.txt:
variable vx equal vx[1]
variable vy equal vy[1]
variable vz equal vz[1]
variable time equal step*dt
fix extra all print 100 "${time} ${vx} ${vy} ${vz}" file ../DEM/post/velocity.txt title "%" screen no
and part of the result is:
0.177 0 0 0
0.178 0 0 0
0.179 0 0 0
0.18 0 0 0
0.181 0 0 0
0.182 0 0 0
0.183 0 0 0
0.184 0 0 0
0.185 0 0 0
0.186 0 0 0
0.187 0 0 0
0.188 0 0 0
0.189 0 0 0
0.19 0 0 0
0.191 0 0 0
0.192 0 0 0
0.193 0 0 0
0.194 0 0 0
0.195 0 0 0
0.196 0 0 0
0.197 0 0 0
0.198 0 0 0
0.199 0 0 0
0.2 0 0 0
84298
0.101 3.305429231e-06 -0.6873107225 0.0003548327532
0.102 3.243836032e-06 -0.6902816765 0.0003619531102
0.103 3.18580197e-06 -0.6933473226 0.0003671387779
0.104 3.126843635e-06 -0.6959309293 0.0003749225884
0.105 3.066019964e-06 -0.6986270441 0.0003844831673
0.106 3.007559591e-06 -0.7014587956 0.0003916518296
0.107 2.953237757e-06 -0.7039317045 0.0003964930432
0.108 2.897214264e-06 -0.7065224861 0.0004036373534
0.109 2.843297059e-06 -0.7092530989 0.0004088482823
0.11 2.792342635e-06 -0.7120869593 0.0004124308496
0.111 2.732861946e-06 -0.7144235545 0.000420106417
I do not know why there is a single data 84298 in these lines and why the time column become inconsistent after the data 84298.
This is what a typical error is when I run simulation of a coupling process.
Cheers,
Tao