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想问一下各位大佬，为什么红圈部分的颗粒没有堆积这种现象呢，颗粒数目是20000个，半径是0.005m。整个流体域是6*4*1，不太明白，请求各位大佬解答

请问还可以用什么命令定义颗粒的直径和密度呢？
create_atoms和set吗？
是的话怎么用呢，求大佬举例，不胜感激

github上搜一下cfdem就能找到

@chapaofa 大佬辛苦啦，我跑就是这样，不知道为啥，感觉命令没问题，我换台电脑试试吧。谢谢啦!

找到了这样一句话

In a worst-case scenario, this can blow particles out of the simulation box. Thus, as a general rule you should not use the fix wall/gran/region command with union or interesect regions that have convex points or edges resulting from the union/intersection (convex points/edges in the union/intersection due to a single sub-region are still OK).

不知道是不是原因，看不太懂，求解答

最近想用liggghts做一个算例，但是出了一点问题

在用fix wall/gran设置墙壁的时候没有效果，粒子还是会从边界穿出去，对照另一个算例写的命令整体差不多，但是那个算例就能挡住粒子，不知道为什么

这是我仿真图，粒子会从边界右边出来

这是那个算例，颗粒可以堆积

下面是我的命令，有大佬可以帮我看看问题一在哪吗，不胜感激！！

atom_style      granular
atom_modify     map array
boundary        f f f
newton          off
communicate     single vel yes
units           si

region          domain block -3 3 0 4 0 1 units box
create_box      1 domain


neighbor        0.004 bin
neigh_modify    delay 0

pair_style  gran model hertz tangential history
pair_coeff  * *

timestep    0.00001

fix integr all nve/sphere
fix gravity all gravity 9.81 vector 0.0 -1.0 0.0

fix m1 all property/global youngsModulus peratomtype 1e6
fix m2 all property/global poissonsRatio peratomtype 0.42
fix m3 all property/global coefficientRestitution peratomtypepair 1 0.9
fix m4 all property/global coefficientFriction peratomtypepair 1 0.1
fix m5 all property/global coefficientRollingFriction peratomtypepair 1 0.5


fix	wallxmin all wall/gran model hertz tangential history primitive type 1 xplane -2.95
fix	wallxmax all wall/gran model hertz tangential history primitive type 1 xplane 2.95
fix	wallymin all wall/gran model hertz tangential history primitive type 1 yplane 0.0
fix	wallymax all wall/gran model hertz tangential history primitive type 1 yplane 3.8
fix	wallzmin all wall/gran model hertz tangential history primitive type 1 zplane 0.0

fix pts1 all particletemplate/sphere 123575 atom_type 1 density constant 1000 radius constant 0.002
fix pdd1 all particledistribution/discrete 123457 1 pts1 1.0

region	spray block -2.8 -2.0 2.0 3.0 0.2 0.8 units box
fix	push all addforce 0.01 0.0 0.0 region spray

region	fire block -2.7 -2.2 3.0 3.6 0.4 0.6 units box
fix  ins1 all insert/rate/region seed 5330 distributiontemplate pdd1 nparticles 10000 particlerate 10000 vel constant 0.0 0.0 -1.0 &
    insert_every 500 overlapcheck yes region fire ntry_mc 10000

thermo          1000
thermo_modify   lost ignore norm no
compute_modify  thermo_temp dynamic yes

run 1

dump dmp all custom 200 post/liggghts_init_*.liggghts id type x y z vx vy vz fx fy fz omegax omegay omegaz radius
     
run 100000 upto