May 17th
Hello,
What I want to do is to simulate the process of EDM(Electrical Discharge Machining).The essence of EDM is a channel of plasma (ionized, electrically conductive gas with high
temperature) formed between the electrodes and develops further with discharge duration. So I use a heat source to simulate the discharge process in EDM. Firstly ,I created a box with Cu(copper) atoms ,like the figure1 shows below .
figure1 :simulation box
Secondly, I try to use the fix temp/rescale command to control
temperature at 7000K by velocity rescaling . The region of atoms that I use this command is always the surface of the simulation box. And it would be a irregular region , like the figure2
shows below . What the red lines show is the region that needs
fix temp/rescale command .
figure2:the surface region changes with time
What I want to ask is that whether lammps can define this
irregular region like the red lines in figure2.
I really appreciate your help~
My in.file is showed below.
units metal
boundary s s s
atom_style atomic
neighbor 2.0 bin
neigh_modify every 5 delay 0 check yes
#create geometry
lattice fcc 3.61
region box block -30 30 -30 30 0 32
create_box 3 box
create_atoms 1 box
#EAM potentials
pair_style eam
pair_coeff * * Cu_u3.eam
#define groups
region 1 block -30 -27.5 -30 30 0 32
region 2 block 27.5 30 -30 30 0 52
region 3 block -27.5 27.5 -30 -27.5 0 32
region 4 block -27.5 27.5 27.5 30 0 32
region 5 block -27.5 27.5 -27.5 27.5 0 2.5
region 6 union 5 1 2 3 4 5
group fixed region 6
region 7 block -27.5 -26 -27.5 27.5 2.5 32
region 8 block 26 27.5 -27.5 27.5 2.5 32
region 9 block -26 26 -27.5 -26 2.5 32
region 10 block -26 26 26 27.5 2.5 32
region 11 block -26 26 -26 26 2.5 4
region 12 union 5 7 8 9 10 11
group thermostat region 12
group mobile subtract all fixed thermostat
set group fixed type 2
set group thermostat type 3
#initial velocities
compute new thermostat temp
compute new2 mobile temp
velocity thermostat create 300.0 887723 temp new
velocity mobile create 300.0 887723 temp new2
velocity fixed create 300.0 887723 loop local
#fixes
fix 1 all nve
fix 2 thermostat temp/rescale 5 300.0 300.0 3.0 1.0
fix_modify 2 temp new
fix 3 mobile temp/rescale 5 300.0 300.0 3.0 1.0
fix_modify 3 temp new2
velocity fixed set 0.0 0.0 0.0
fix 4 fixed setforce 0.0 0.0 0.0
timestep 0.002
thermo 200
thermo_modify lost ignore flush yes
run 20000
region 13 cylinder z 0 0 8 31 32
#the beginning region of fix temp/rescale command and I donot
know how to define the next region
group kinetic region 13
compute new1 mobile temp/region 28
velocity kinetic scale 7000 dist gaussian
unfix 3
fix 5 mobile temp/rescale 10 7000.0 7000.0 10.0 1.0
fix_modify 5 temp new1
run 2400
unfix 5
run 15000
Nafens
mail1.pdf (270 KB)