Granular Matter

Ein kleiner Film, der die Musterbildung zeigt. Er wurde für den Tag der offenen Tür der Universität 1999 produziert und soll Nicht-Wissenschaftler beeindrucken. Der Kopf, der sich bildet, ist das Porträt von Otto von Guericke, Bürgermeister von Magdeburg, der als erster die Wirkung des Luftdrucks über 2 evakuierte Halbkugeln aus Eisen demonstrierte. Das Porträt ist das Siegel der Universität Magdeburg. Es verdeutlicht auch die Vielseitigkeit unseres Programms.

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 short movie showing pattern formation. This was produced for the ICA1 of the University of Stuttgart.

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 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.

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.

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

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. 

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.

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.