insertion mode stream command

Purpose

insertion mode stream is used to generate a continuous particle stream that originates from a face (examples).

Syntax

insertion mode stream keyword value

General insertion keywords are documented here. This document only describes the specific keywords for the insertion of a stream of particles.

Return to the insertion documentation.

Keywords

Description

insertion_face ¹

ID of the mesh command to use as starting face for particle generation

insertion_shape ¹
shape through which the particles should be inserted, allowed values are: circle, ellipse
square, rectangle (keywords see here)

massrate ²
mass insertion rate
range: (0,∞); units: [mass / time]

particlerate ²
particle insertion rate
range: [1,∞); units: [1/time]

target_mass ³
desired mass to insert
range: (0,∞); units: [mass]

target_particle_count ³
desired number of particles to be inserted each time
range: [1,∞); units: [-]

extrude_length
length for extruding the insertion face in normal direction so to generate in insertion volume
mutually exclusive with insert_every_time (see insert_every_time)
range: (0,∞); units: [length]

parallel
yes or no; pre-calculate location of overlap of processor subdomains and extrusion volume
to some extent
default: no

duration_time
duration of each insertion moment (insert_every_time) in time units
range: (0,`insert_every_time`); units: [time]

volume_limit
minimal volume of the insertion region used for sanity checks
range: (0,∞); units: [distance^3]
¹ The keywords insertion_face and insertion_shape are mutually exclusive, one of them is obligatory.
² The keywords particlerate and massrate are mutually exclusive.
³ The keywords target_particle_count and target_mass are mutually exclusive.

Examples

insertion mode stream particle_distribution pdd1 massrate 0.1 velocity constant (0, 0, -1) &
     insertion_face my_insertion_face

insertion mode stream particle_distribution pdd1 target_particle_count 6000 massrate 0.1 &
     insert_every_time 0.01 all_in no velocity constant (0, 0, -1) &
     insertion_shape circle center (0, 0, 0.5) radius 0.1

insertion mode stream particle_distribution pdd1 target_mass 30 massrate 30 velocity constant (0, 0, -1) &
     insertion_shape rectangle center (0, 0.1, 0.3) x_axis (1, 1, 0) x_length 0.1 y_length 0.05 extrude_length 0.1

insertion mode stream particle_distribution pdd1 target_particle_count 6000 massrate 0.1 &
     insert_every_time 1e-3 duration_time 5e-4 all_in no velocity constant (0, 0, -1e-3) &
     insertion_shape square center (0, 0, 0.5) x_axis (1, 0, 0) length 1e-6 volume_limit 1e-18

Description

The insertion_face keyword accepts the id of a mesh command. The mesh itself can have any shape but must be planar. Note that the insertion face can be a mesh with a mesh_module of type motion to yield a moving insertion. The mesh must be a planar face and the insertion velocity projected on the face normal must be non-zero.

Alternatively, a generic insertion_shape can be used, the options circle, ellipse, square and rectangle are available. More information and keywords for the generic insertion shapes can he found here.

This insertion command randomly places particles inside an insertion volume that is calculated from the insertion face or shape, the insertion interval and the particle velocity. By setting the massrate or the particlerate, the intensity of the insertion is determined.

If neither of the quantities is defined, a case-dependent default particle rate is inserted.

The keywords target_mass and target_particle_count can be used to set the overall material amount that is inserted.

The “number of particles” always applies to the number of particle templates / particle conglomerates for composed particles such as multispheres, fibers or concave triangulated particles.

This keyword is an alternative to the insert_every_time keyword. Together with the insertion face or shape it defines the insertion volume, the insertion time interval is then calculated from the insertion volume and the insertion velocity.

The duration_time keyword can be used for the definition of pulsed insertions. It has to be used in combination with insert_every_time and its value must be lower than the insert_every_time value.

If the keyword parallel is set to yes, Aspherix® tries to pre-calculate more accurately the overlap of process subdomains and extrusion volume. For cases where the insertion volume is highly divided between different processes, this can lead to a speed-up of insertion as random number generation is more efficient. For cases where the extrusion volume is divided among few processes this will impose a small computation overhead.