"Flying Particles" at low Reynolds number

The following simulation addresses the movement of particles in a square. The path of single particles is prescribed and the merger of several objects is allowed! In this simulation, we apply "natural boundary conditions" at the edges of the square. The movement of the particles is prescribed by the "Fictitious Boundary Conditions" only: All calculations are performed on ONE SINGLE mesh!!! This explains why the contour of the particles is sometimes poorly represented, particularly if streamfunction or pressure plots are used! In addition, the visualization of the pressure is very hard due to the extrema which arise if particles come closer and closer!

• Velocity
  
  

  Visualization via normalized (via color) plots (shaded, 1.4 MB, and vector, 6.2 MB) and "real sized" vectors (11.1 MB).
  

  
  
  

• Pressure
  
  

  Visualization via shaded pressure plots (0.6 MB) and via isolines (second, 3.2 MB).
  

  
  
  

• Streamfunction
  
  

  Visualization via shaded streamline plots (0.5 MB) and via isolines (8.3 MB).