Dear Users,
I am simulating thermal conductivity of a system using NEMD. The c- dimension of the system is ~120 Angstrom.
I equilibrated the system about 80 ps. there after the calculation of temperature gradient has started. Following is the heat and cold junction temperature and difference
Step Temp c_Thot c_Tcold v_tdiff f_ave
40000 503.01586 522.77312 557.53275 0 0
41000 507.2842 554.36045 509.07491 -2.8993005 -1.4496502
42000 490.67764 514.83435 454.89508 -1.1528129 -1.3507044
43000 496.96574 520.92135 489.96429 -53.404155 -14.364067
44000 509.93966 531.02526 456.68109 -25.386426 -16.568539
45000 515.4765 460.40177 493.98522 -45.444148 -21.38114
46000 498.64148 520.34094 464.01641 -73.248267 -28.79073
47000 511.21223 577.20131 487.54003 -49.117953 -31.331633
…
The data seems to be very zig-zag. Also I am not sure/understand why v_tdiff is not equal to the difference between hot and cold junctions.
I also checked the heat profile file and it also shows that the heat gradient between heat and cold junction is not uniform:
# Chunk-averaged data for fix 2 and group file
# Timestep Number-of-chunks Total-count
# Chunk Coord1 Ncount v_temp
41000 20 2688
1 0.025 128.82 524.017
2 0.075 135.31 519.816
3 0.125 140.65 525.407
4 0.175 135.29 537.268
5 0.225 133.08 534.813
6 0.275 131.25 479.673
7 0.325 135.58 465.321
8 0.375 139.82 488.772
9 0.425 133.79 482.885
10 0.475 134.1 506.099
11 0.525 130.34 521.118
12 0.575 132.73 520.463
13 0.625 140.51 479.076
14 0.675 137.94 453.716
15 0.725 128.31 498.588
16 0.775 132.34 499.708
17 0.825 131.72 494.511
18 0.875 140.87 503.413
19 0.925 130.05 487.929
20 0.975 135.5 506.953
42000 20 2688
1 0.025 130.04 512.829
2 0.075 134.58 521.133
3 0.125 140.69 505.265
4 0.175 134.9 524.525
5 0.225 132.59 531.471
6 0.275 132.5 476.407
7 0.325 133.62 505.346
8 0.375 139.83 478.997
9 0.425 133.88 464.688
10 0.475 132.76 515.242
11 0.525 130.29 511.676
12 0.575 133.4 520.298
13 0.625 142.13 494.738
14 0.675 133.9 473.821
15 0.725 130.47 476.393
16 0.775 132.36 465.298
17 0.825 131.97 517.776
18 0.875 142.41 487.97
19 0.925 134.44 504.769
20 0.975 131.24 503.621
…
Please advise.
Thanks,
Mayank