"Flying Particles" flow 
The following examples concern flow in a chamber with moving particles of different size.
The aim of the following simulations is just to demonstrate the utility of our "Fictitious Boundary Conditions": All calculations are performed on ONE SINGLE mesh which does not change! The position of the actual boundary is determined via "filters" and incorporated into the iterative solvers! A more detailed description of the underlying mathematical and numerical concepts is given in Stefan Turek's CFDbook, Springer. The "true" complexity of the physical problem depends on the:
While in reality the particles will change their flow behaviour if they approach one another  up to a collision!!!  we allow in the following simulations the "nonphysical" event that two or even several particles build one single "macroparticle"  for a short lifetime! To be concrete: we neglect all implicit behaviour but we prescribe instead a fixed motion of the particles. As pointed out, these tests are for a demonstration of the "Fictitious Boundary Conditions" only while the physical interactions can be added by users who are interested in this topic! 

Please send any comments and suggestions to: featflow@featflow.de 