Granulare Medien, Animation

Not quite a hopper, but a hole in the floor.

A very tiny simulation. 36 balls are being thrown into a container. The rolling of the particles leads to a final configuration, which is virtually flat. 

The walls of the hopper are not as steep as in the other examples. The flow ends when an arch forms spontaneously and the hopper is blocked.

We have a hopper, filled with particles. Additional to the repulsive forces due to collisions we have ceohesive forces. You can find more information in this publication.

A piston is compressing with a certain force onto an assembly of granular materials. No gravity is acting. The Material is very soft, so there are oscillations.

Here a sand pile is build from a line source to demonstrate the importance of static friction in sandheaps. At time step 420 the friction coefficient is quickly reduced to zero. The pile melts and the granulate flows like a liquid. 

The time evolution of the force network of a sand pile which is built from a point source is shown. The width of the blue lines is proportional to the strength of the forces. The red arrows are the forces onto the ground. Note that the avalanches either go left or right and therefore lead always to slight asymmetries of the heap.

For the simulation, we have calculated the stress tensors inside the pile. In this movie, the major principal axis of the stress (crosses) and the pressure on the ground (arrows) are shown. 

This heap is build using 4500 slightly elongated Particles. The first frames shows the evolution of the heap, the bottom frame shows the pressure onto the ground. You can observe the evolution of a dip below the apex of the pile

This heap is the same as the other examples. In the top frame you can see the stress tensors inside of the pile. The second frame shows the forcenetwork; small forces are black, medium forces are red and strong forces are yellow. The 8 small frames show the axis of the major principal axis in the different layers of the pile. The last frame shows the pressure distribution. 

A small movie, showing a tinkertoy-setup involving dominos and a seesaw. This was produced for the open day of the university 1998 and aims to impress non-scientists. It also demonstrates the versatility of our program.

We have a hopper, filled with about 1300 particles. We can see the funnel-flow of the grains. At the end, two particles on the upper left are stuck.

A small film showing pattern formation. This was produced for the ICA1 of the University of Stuttgart.

Now we have the same geometry as in the other funnel, but the shape of the particles was initialized slightly different. The hopper is not blocked.

A small movie, showing pattern formation. This was produced for the open day of the university 1999 and aims to impress non-scientists. The head which forms is the portrait of Otto von Guericke, Mayor of Magdeburg, who first demonstrated the effect of air pressure via 2 evacuated half-spheres made from iron. The portrait is the seal of the University of Magdeburg. It also demonstrates the versatility of our program.

Penguins, penguins, everywhere are pinguins... A movie for the former supercomputer Tina.

The Galton Board is a device to explain binomial distributions. It consists of a board that has a large amount of pins fixed to it. These pins are arranged in regular horizontal rows so that the pins form a triangle with its base at the bottom of the board.

Dieser Film zeigt den Einsturz eines Kartenhauses. Die Setup-Datei wurde mit Hilfe von xfig erstellt. Ohne die Implementierung eines Gesetzes für Coulomb/statische Reibung wäre die Anfangskonfiguration nicht stabil.

This setup is shows the behaviour of granular material in a vibrating box. Due to the small wall, the system can break the symmetrie.

This  example shows a hopper with a small outlet and a few large particles. The hopper blocks twice. The clogging is removed by tapping the hopper, so that all particles are accelerated upwards.