diff --git a/doc/src/fix_wall_stochastic.txt b/doc/src/fix_wall_stochastic.txt index 5caba6d6b9..290768549e 100644 --- a/doc/src/fix_wall_stochastic.txt +++ b/doc/src/fix_wall_stochastic.txt @@ -1,102 +1,102 @@ -"LAMMPS WWW Site"_lws - "LAMMPS Documentation"_ld - "LAMMPS Commands"_lc :c - -:link(lws,http://lammps.sandia.gov) -:link(ld,Manual.html) -:link(lc,Commands_all.html) - -:line - -fix wall/stochastic command :h3 - -[Syntax:] - -fix ID group-ID wall/stochastic reflectionstyle face pos temp velx vely velz accomx accomy accomz ... :pre - -ID, group-ID are documented in "fix"_fix.html command :ulb,l -wall/stochastic = style name of this fix command :l -one or more face/arg pairs may be appended :l -reflectionstyle = diffusive or maxwell or cercignanilampis :l -face = {xlo} or {xhi} or {ylo} or {yhi} or {zlo} or {zhi} :l - {xlo},{ylo},{zlo} pos = EDGE or constant - EDGE = current lo edge of simulation box - constant = number like 0.0 or -30.0 (distance units) - temp = wall temperature - velx, vely, velz = wall velocity along x, y, z directions - accomx, accomy, accomz = accommodation coefficients along x, y, z directions (only for maxwell and cercignanilampis reflection style) - {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) - temp = wall temperature - velx, vely, velz = wall velocity along x, y, z directions - accomx, accomy, accomz = accommodation coefficients along x, y, z directions (only for maxwell and cercignanilampis style) :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 zwalls all wall/stochastic diffusive zlo EDGE 300 0.1 0.1 0 zhi EDGE 200 0.1 0.1 0 -fix ywalls all wall/stochastic maxwell ylo 5.0 300 0.1 0.0 0.0 0.8 yhi 10.0 300 0.1 0.0 0.0 0.8 -fix xwalls all wall/stochastic cercignanilampis xlo 0.0 300 0.0 0.1 0.9 0.8 0.7 xhi EDGE 300 0.0 0.1 0 0.9 0.8 0.7 units box :pre - -[Description:] - -This fix differs from the command fix wall/reflect which is equivalent -to the mirror reflection in that the post collision velocity of the atoms -in the stochastic wall is random. The randomness can come from many sources: -thermal motion of solid atoms, the surface roughness, etc... Three -stochastic wall models are implemented. - -Diffusive wall (reflectionstyle = diffusive): all the gas atoms are -reflected diffusively. Their velocity distribution corresponds to the -equilibrium distribution at the wall temperature. - -Maxwell model (reflectionstyle = maxwell): the reflection is partially -diffusive and partially specular. The accommodation coefficient is the -portion of the diffusive reflection "Maxwell"_#Maxwell. - -Cercignani/Lampis model: 3 accommodations coefficients are used, two -velocity accommodation coefficients and one normal kinetic energy -accommodation "CL"_#CL, "To"_#To. 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. - -:line - -[Restrictions:] - -Due to the similarities, this fix has the same limitation as the the -wall/reflect. Any dimension (xyz) that has a wall must be non-periodic. It -should not be used with rigid bodies such as those defined by a "fix rigid" -command. Furthermore, the wall velocity must lie on the same plane as the wall. Package USER-MISC is required to use this fix. - -[Related commands:] - -"fix wall/reflect"_fix_wall_reflect.html, - -[Default:] none - -:line - -:link(Maxwell) -[(Maxwell)] J.C. Maxwell, Philos. Tans. Royal Soc. London, 157: 49-88 (1867). - -:link(CL) -[(Cercignani)] C. Cercignani and M. Lampis. Trans. Theory Stat. Phys. 1, 2, 101 (1971). - -:link(To) -[(To)] Q.D. To, V.H. Vu, G. Lauriat, and C. Leonard. J. Math. Phys. 56, 103101 (2015). - +"LAMMPS WWW Site"_lws - "LAMMPS Documentation"_ld - "LAMMPS Commands"_lc :c + +:link(lws,http://lammps.sandia.gov) +:link(ld,Manual.html) +:link(lc,Commands_all.html) + +:line + +fix wall/stochastic command :h3 + +[Syntax:] + +fix ID group-ID wall/stochastic reflectionstyle seed face pos temp velx vely velz accomx accomy accomz ... :pre + +ID, group-ID are documented in "fix"_fix.html command :ulb,l +wall/stochastic = style name of this fix command :l +one or more face/arg pairs may be appended :l +reflectionstyle = diffusive or maxwell or cercignanilampis :l +seed = random seed for stochastic wall (must be less than 900000000) :l +face = {xlo} or {xhi} or {ylo} or {yhi} or {zlo} or {zhi} :l + {xlo},{ylo},{zlo} pos = EDGE or constant + EDGE = current lo edge of simulation box + constant = number like 0.0 or -30.0 (distance units) + temp = wall temperature + velx, vely, velz = wall velocity along x, y, z directions + accomx, accomy, accomz = accommodation coefficients along x, y, z directions (only for maxwell and cercignanilampis reflection style) + {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) + temp = wall temperature + velx, vely, velz = wall velocity along x, y, z directions + accomx, accomy, accomz = accommodation coefficients along x, y, z directions (only for maxwell and cercignanilampis style) :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 zwalls all wall/stochastic diffusive 23424 zlo EDGE 300 0.1 0.1 0 zhi EDGE 200 0.1 0.1 0 +fix ywalls all wall/stochastic maxwell 345533 ylo 5.0 300 0.1 0.0 0.0 0.8 yhi 10.0 300 0.1 0.0 0.0 0.8 +fix xwalls all wall/stochastic cercignanilampis 2308 xlo 0.0 300 0.0 0.1 0.9 0.8 0.7 xhi EDGE 300 0.0 0.1 0 0.9 0.8 0.7 units box :pre + +[Description:] + +This fix differs from the command fix wall/reflect which is equivalent +to the mirror reflection in that the post collision velocity of the atoms +in the stochastic wall is random. The randomness can come from many sources: +thermal motion of solid atoms, the surface roughness, etc... Three +stochastic wall models are implemented. + +Diffusive wall (reflectionstyle = diffusive): all the gas atoms are +reflected diffusively. Their velocity distribution corresponds to the +equilibrium distribution at the wall temperature. + +Maxwell model (reflectionstyle = maxwell): the reflection is partially +diffusive and partially specular. The accommodation coefficient is the +portion of the diffusive reflection "Maxwell"_#Maxwell. + +Cercignani/Lampis model: 3 accommodations coefficients are used, two +velocity accommodation coefficients and one normal kinetic energy +accommodation "CL"_#CL, "To"_#To. 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. + +:line + +[Restrictions:] + +Due to the similarities, this fix has the same limitation as the the +wall/reflect. Any dimension (xyz) that has a wall must be non-periodic. It +should not be used with rigid bodies such as those defined by a "fix rigid" +command. Furthermore, the wall velocity must lie on the same plane as the wall. Package USER-MISC is required to use this fix. + +[Related commands:] + +"fix wall/reflect"_fix_wall_reflect.html, + +[Default:] none + +:line + +:link(Maxwell) +[(Maxwell)] J.C. Maxwell, Philos. Tans. Royal Soc. London, 157: 49-88 (1867). + +:link(CL) +[(Cercignani)] C. Cercignani and M. Lampis. Trans. Theory Stat. Phys. 1, 2, 101 (1971). + +:link(To) +[(To)] Q.D. To, V.H. Vu, G. Lauriat, and C. Leonard. J. Math. Phys. 56, 103101 (2015).