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fix massflow/mesh/sieve command

Syntax:

fix id group massflow/mesh/sieve mesh mesh-ID point_at_outlet pointX pointY pointZ keyword value ... 

Example:

fix     massFlow1 all massflow/mesh/sieve mesh massFlow1M point_at_outlet 0 0 -1000 count once delete_atoms no file massFlow1.dat sieveSize 2e-3 sieveSpacing 2.5e-3 sieveStiffness 1e5 sieveDamping 1e3 

Description:

This fix is an extension of the fix "massflow/mesh", so the reader may wish to consult also the documentation of this fix for further details.

Fix massflow/mesh/sieve models a sieve, and counts the particles that cross the sieve (same as in massflow/mesh). The sieve is modeled with circular holes in a the mesh (the holes have a certain spacing), and a passage probability is computed based on the particle diameter. Thus, a probability is computed based on the relative area that would result into particle passage divided by the total cross-sectional area of the sieve, assuming particles move perfectly normal to the mesh. This probability is evaluated at the first time step of every collision event, and compared with a uniformly-distributed random number. Thus, sliding contacts, or multiple collision may not by modelled accurately.

Restrictions:

Currently, this feature does not allow deleting multi-sphere particles when crossing the sieve. Also, it is strongly recommended to NOT activate sieveMultiSphereCanPass, since this feature is not tested in high detail. For example, it may occur that multisphere particles may get stuck when passing the sieve.

Related commands:

compute nparticles/tracer/region fix massflow/mesh

Default:

sieveDamping = 0; sieveMultiSphereCanPass = false; all other parameters need to be set by the user.