Syntax:
compute ID surf/reaction/tally group-ID mix-ID value1 value2 ...
reaction = which reaction occurred (1 to N) id/surf = surface element ID id/pre = particle ID before reaction id1/post = particle ID of first particle after reaction id2/post = particle ID of second particle after reaction type/pre = particle species before reaction type1/post = particle species of first particle after reaction type2/post = particle species of second particle after reaction time = time of collision (within timestep, see below) xc, yc, zc = coordinates of collision point vx/pre, vy/pre, vz/pre = velocity components before reaction vx1/post, vy1/post, vz1/post = velocity components of first particle after reaction vx2/post, vy2/post, vz2/post = velocity components of second particle after reaction
Examples:
compute 1 surf/reaction/tally all all reaction id/pre id1/post id2/post type/pre type1/post type2/post id/surf time xc yc zc
This command will dump the tallies in the previous command to a dump file every 10 steps:
dump 1 tally all 10 tmp.tally c_1[*]
Description:
Tally various values for each reaction of a particle with a surface element during the current timestep. Only surface collisions which result in a chemical reaction are tallied by this command, as enabled by the surf_react command. See the related compute surf/collision/tally command to tally collisions which do not induce reactions. It provides different tally value options than this compute.
Only surface elements in the surface group specified by group-ID and particles with species in the mixture specified by mix-ID are included. See the group grid command for info on how surface elements can be assigned to surface groups.
This compute can be used for simulations with either explicit or implicit surface elements. See Section 6.13 for more discussion of explicit and implicit surfaces.
The results of this compute can be used by different commands in different ways. The values for a single timestep can be output by the dump tally command. Currently this is the only option for accessing the tallied values.
Note that if a gas/surface reaction takes place, then a collision of a single particle with a surface can result in 0, 1, or 2 particles being produced. The species of the product particles may be different than the species of the reactant. All of these attributes can be tallied using the values explained next.
The reaction value is the index of which reaction occurred. It is a number from 1 to N, where N is the number of reactions defined by the surf_react command.
The id/surf value is the ID of the surface element. For explicit surfaces, surface element IDs are unique. For implicit surfaces, the surface ID of all the surface elements within a grid cell are the grid cell ID. See Section 6.13 for more discussion of explicit and implicit surfaces.
The id/pre value is the ID of the incident particle. Note that particle IDs are generated randomly. Thus multiple particles in the system can potentially have the same ID. See Section 6.17 for more details on particle IDs.
The id1/post and id2/post values are the post-collision IDs of the 0, 1, or 2 resulting particles. If the incident particle vanished in the reaction, then id1/post will be 0. Otherwise it will be the same as id/pre. If id2/post is 0, no 2nd particle was created by the reaction, otherwise it is the random ID assigned to the newly created particle.
The type/pre value is the integer index for the incident particle species. It is a value from 1 to Nspecies. The value corresponds to the order in which species were defined via the species command. See Section 6.17 for more details on particle types.
The type1/post and type2/post values are the post-collision integer indices for the particle species of the 0, 1, or 2 resulting particles. If the incident particle vanished in the reaction, then type1/post will be 0. Otherwise type1/post is the new species index of the incident particle. If type2/post is 0, no 2nd particle was created by the reaction, otherwise it is the species index of the newly created particle.
The time value is the point in time within the timestep when the collision occured. Thus if the timestep size is DT, as set by the timestep command, the time values will all be within the range of 0.0 to DT, for all collisions tallied by this compute on each timestep it is invoked.
The xc, yc, and zc are the coordinates of the collision point between the particle and the surface element.
The vx/pre, vy/pre, vz/pre values are the velocity components of the incident particle before it collides with the surface element.
The vx1/post, vy1/post, vz1/post values are the velocity components of the incident particle after it collides with the surface element and has reacted. These values will be zero if the paticle vanished in the reaction.
If a 2nd particle was created by the reaction, the vx2/post, vy2/post, vz2/post values are its velocity components. If no 2nd particle was created, these values will be zero.
Output info:
This compute calculates a per-tally array, with the number of columns equal to the number of values.
The array can be accessed by any command that uses per-tally values from a compute as input. See Section 6.4 for an overview of SPARTA output options.
The per-tally array values will be in the units appropriate to the individual values as described above. Time is in time units; see above for details. Xc, yc, and zc are in distance units. Vx/pre, vy/pre, vz/pre are in velocity units, as are vx1/post, vy1/post, vz1/post and vx2/post, vy2/post, vz2/post.
Restrictions: none
Related commands:
compute surf/collision/tally, compute gas/reaction/tally, dump tally
Default: none