Delete fix_wall_cl.txt

"LAMMPS WWW Site"_lws - "LAMMPS Documentation"_ld - "LAMMPS Commands"_lc :c

:link(lws,http://lammps.sandia.gov) link(ld,Manual.html)

:link(lc,Section_commands.html#comm)

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fix wall/cl command :h3

[Syntax:]

fix ID group-ID wall/cl face pos temp velx vely velz keyword value ... :pre

ID, group-ID are documented in "fix"_fix.html command :ulb,l

wall/cl = style name of this fix command :l

one or more face/arg pairs may be appended :l

face = {xlo} or {xhi} or {ylo} or {yhi} or {zlo} or {zhi} :l

  {xlo},{ylo},{zlo} pos = EDGE or constant or variable

    EDGE = current lo edge of simulation box

    constant = number like 0.0 or -30.0 (distance units)

    variable = "equal-style variable"_variable.html like v_x or v_wiggle

    temp = wall temperature

    velx, vely, velz = wall velocity along x, y, z directions

    accomx, accomy, accomz = accommodation coefficients along x, y, z directions

  {xhi},{yhi},{zhi} pos = EDGE or constant or variable

    EDGE = current hi edge of simulation box

    constant = number like 50.0 or 100.3 (distance units)

    variable = "equal-style variable"_variable.html like v_x or v_wiggle 

    temp = wall temperature 

    velx, vely, velz = wall velocity along x, y, z directions

    accomx, accomy, accomz = accommodation coefficients along x, y, z directions

    :pre

zero or more keyword/value pairs may be appended :l

keyword = {units} :l

    {units} value = {lattice} or {box}

    {lattice} = the wall position is defined in lattice units

    {box} = the wall position is defined in simulation box units :pre

:ule

[Examples:]

fix ywalls all wall/cl xlo EDGE 300 0.1 0.1 0 0.8 0.8 0.9 xhi EDGE 200 0.1 0.1 0

0.8 0.8 0.9

fix ywalls all wall/cl xlo 300 0.1 0.1 0 ylo 300 0.1 0.1 0 0.9 0.8 0.7 units box

:pre

[Description:]

Cercignani-Lampis (CL) "CL"_#CL propose a stochastic wall model which can model

the gas-wall collision realistically. Instead of mixing wall/reflect and

wall/diffusive as in Maxwell model (fix wall/maxwell), the CL model used shifted

MB distribution for the tangential velocity and exponential bessel for the

normal velocity. Two accommodation coefficients are used: one for the tangential

velocity (isotropic) and one for the normal kinetic energy. In this fix, a

generalized version "To"_#To which can account for the anisotropy of the wall

surface is implemented, there are three coefficients: two for the tangential

velocity (two components) and one for the kinetic energy. The code will

recognize automatically the normal direction of the wall and the other two

tangential directions. For example, if accomx = 0.5, accomy = 0.2, accomz = 0.3

and the wall is normal to direction y, accomx and accomz are the tangential

velocity accommodation coefficients and accomy is the normal kinetic energy

accommodation coefficients.

The {units} keyword determines the distance units used to define a wall position

A {box} value selects standard distance units as defined by the

"units"_units.html command, e.g. Angstroms for units = real or metal. 

A {lattice} value means the distance units are in lattice spacings. The

"lattice"_lattice.html command must have been previously used to define the

lattice spacings.

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[Restrictions:]

Due to its properties, this fix has has the same limitation as the the

wall/reflect. Any dimension (xyz) that has a wall must be non-periodic. It

shoudld not be used with rigid bodies such as those defined by a "fix rigid"

command. 

[Related commands:]

"fix wall/reflect"_fix_wall_reflect.html, "fix

"wall/maxwell"_fix_wall_maxwell.html, "fix

"wall/diffusive"_fix_wall_diffusive.html

[Default:] none

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:link(CL) 

[(CL)] Cercignani and M. Lampis, "Kinetic models for gas-surface

interactions" Transp. Theory Stat. Phys. 1, 2, 101 (1971). 

:link(To) 

[(To)] Q.D.

To, V.H. Vu, G. Lauriat, and C. Leonard, "Boundary conditions for gas flow

problems from anisotropic scattering kernels" J. Math. Phys. 56, 103101 (2015).