Dear Users,

I am modeling pressure driven flow in a nano-channel. For calculating the pressure gradient along the channel I have to use stress/atom command in bins. As a first step, I ran the sample command given in the documentation.

Command used to calculate pressure,

compute peratom all stress/atom NULL

compute p all reduce sum c_peratom[1] c_peratom[2] c_peratom[3]

variable press equal -(c_p[1]+c_p[2]+c_p[3])/(3*vol)

thermo_style custom step temp c_tu c_tl c_tf **press** **v_press**

The last two terms in thermo output are not matching. (the difference in the value is persisting and the first term is larger than the second)

NOTE:

Pair modify command is not used in the script.

Thanking in advance for your kind help.

ABDUL GAFOOR C P

Dear Users,

I am modeling pressure driven flow in a nano-channel. For calculating

the pressure gradient along the channel I have to use stress/atom

command in bins. As a first step, I ran the sample command given in

the documentation.

Command used to calculate pressure,

compute peratom all stress/atom NULL

compute p all reduce sum c_peratom[1] c_peratom[2] c_peratom[3]

variable press equal -(c_p[1]+c_p[2]+c_p[3])/(3*vol)

thermo_style custom step temp c_tu c_tl c_tf *press* *v_press*

The last two terms in thermo output are not matching. (the difference

in the value is persisting and the first term is larger than the second)

Does your simulation box contains a lot of vacuum? I assume that the

equivalence between press and v_press is valid only in the case of

"continuous" system. No?

Julien.

Sir,

I am modeling an Argon gas flow in nano-channel with a Knudsen Number 0.066.

Is there any other way to monitor the pressure in thermo output when our system is not continuous?

Regards

ABDUL GAFOOR