Dear users,
i simulated a collision bewteen a particle and block. i defined three groups for block and a group for particle. what i care is the temperature of the bulk_upper group and particle group. Therefore, i compute and monitor their temperature step by step.
unexpectedly, the temperature of the bulk_upper group and thermo_temp is the same as the specified temperature, while the temperature of particle_upper group (T_upper ) is much lower. I don’t understand this. Whether the NVT does not control the whole temperature or anything was wrong in the script.
(btw: i had alread posted one similar subject. Hope i present clearly my question this time and not waste time again.)
input and log
units real
dimension 3
newton on
boundary p p p
atom_style hybrid charge atomic
communicate multi vel yes
neighbor 2.0 nsq
neigh_modify delay 0 every 1 check yes page 100000 one 10000
timestep 0.5
--------------------------definitiophere------------------
read_data data.TIO
orthogonal box = (-30 -30 -30) to (30 30 100)
1 by 1 by 1 MPI processor grid
4335 atoms
#---------------Matsui-Akaogi potential-----------------------
pair_style buck/long/coul/long cut long 10.0
pair_coeff 1 1 7.177e+5 0.154 1.210e+2
pair_coeff 1 2 3.911e+5 0.194 2.904e+2
pair_coeff 2 2 2.717e+5 0.234 6.969e+2
pair_modify table 0
kspace_style ewald 1.0e-4
#-------------------------------define group-------------------
group upper id >= 3970 #upper particle
366 atoms in group upper
group bulk_down region 1
467 atoms in group bulk_down
group bulk_middle region 2
759 atoms in group bulk_middle
group bulk_upper region 3
2743 atoms in group bulk_upper
group bulk_down region 1
group bulk_middle region 2
group bulk_upper region 3
###compute
computer energy
compute new all temp
compute 1 all pe/atom
compute kineng_upper upper ke
compute 4 all stress/atom pair
compute T_middle bulk_middle temp
compute bulk_upper bulk_upper temp
compute T_upper upper temp/com
#initial velocity and temp
velocity all create 300.0 123456 dist gaussian units box
#velocity bulk_down set 0.0 0.0 0.0 units box
###fix—relax-nvt------------
fix 1 all nvt temp 300.0 300.0 10.0 drag 0.2
fix 2 bulk_down setforce 0.0 0.0 0.0
thermo 10
thermo_style custom step temp press pe ke etotal c_T_upper v_position_z v_velocity_z c_bulk_upper
thermo_modify lost warn
dump 1 all xyz 5000 dump.xyz.*
dump_modify 1 element Ti O
run 5000
Step Temp Press PotEng KinEng TotEng T_upper position velocity bulk_upper
0 267.20299 48790.853 -989605.84 3451.9502 -986153.89 281.00529 48.411289 0.0001091628 305.95323
1000 331.44517 4010.0177 -1247721 4281.8841 -1243439.2 149.46128 48.412408 -1.1437591e-006 332.52604
2000 301.79636 4620.8873 -1255331.7 3898.8561 -1251432.8 157.78602 48.411879 -1.3459734e-006 309.92492
3000 296.23474 4332.4544 -1257317.7 3827.0064 -1253490.7 178.3174 48.411191 -1.3087518e-006 305.1288
4000 297.65408 4818.3058 -1258478.2 3845.3427 -1254632.9 161.38247 48.410409 -1.8083279e-006 312.27244
5000 300.54857 4639.2941 -1259125.6 3882.7362 -1255242.8 179.54521 48.40944 -1.902138e-006 318.75308
Loop time of 12729.1 on 1 procs for 5000 steps with 4335 atoms
Pair time () = 746.484 (5.86441)
Kspce time () = 11969.7 (94.0347)
Neigh time () = 10.8281 (0.0850662)
Comm time () = 0.15625 (0.00122751)
Outpt time () = 0.203125 (0.00159576)
Other time () = 1.65625 (0.0130116)
Nlocal: 4335 ave 4335 max 4335 min
Histogram: 1 0 0 0 0 0 0 0 0 0
Nghost: 603 ave 603 max 603 min
Histogram: 1 0 0 0 0 0 0 0 0 0
Neighs: 895708 ave 895708 max 895708 min
Histogram: 1 0 0 0 0 0 0 0 0 0
Total # of neighbors = 895708
Ave neighs/atom = 206.622
Neighbor list builds = 84
Dangerous builds = 0
unfix 1
undump 1