Movies on Granular Materials


This movies show the behaviour of granular Materials. We (Hans-Georg Matuttis and Alexander Schinner) have simulated different setups. The simulation was done by a self written program gc2d. The force calculation is described in H. -G. Matuttis, Simulations of the pressure distribution under a two dimensional sand-pile of polygonal particles.. More Information on the highly efficient collision detection you can get in the diploma thesis on "Numerische Simulation granularer Medien" or in the SCE-Proceedings Efficient Collision Detection for MD-Simulations.


tdot.mpg In general, collisions makes granular materials most interesting. For this movie, I tried to avoid collisions!
~2.73 Mb 634 frames
cards.mpg This movie shows the collaps of a house of cards. The Setup file was made with the use of xfig. Without the implementation of a law for Coulomb/ static friciton, the initial configuration would not be stable.
~841 Kb 249 frames
funnel_demo.mpg 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.
~6.25 Mb 275 frames
funnel_ica1.mpg A small movie, showing pattern formation. This was produced for the the ICA1.
~5.29 Mb 275 frames
tina.mpg Penguins, penguins, everywhere are pinguins... Movie for Tina.
~2.1 Mb 275 frames
demo.mpg 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.
~600 Kb 399 frames
speed.mpg 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.
~233 Kb 99 frames
galton.mpg 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. 
~15.6 Mb 2799 frames
gas.mpg This setup is shows the behaviour of granular material in a vibrating box. Due to the small wall, the system can break the symmetrie.
~12.3 Mb 1201 frames
trommel2.mpg A rotating drum with a mixture of many small and a few large particles.
~11.9 Mb 750 frames
funnel_cohesive.mpg We have a hopper, filled with particles. Additional to the repulsive forces due to collisions we have ceohesive forces.
~5.02 Mb 520 frames
piston2.mpg 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 
~1.74 Mb 349 frames
Constructing a Heap from a Point Source 
mid8point1.mpg 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.
~5779 kb 680 frames
mid8point2.mpg This heap is the same as the last example. 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.
~7505 kb 680 frames
forcenet.mpg 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.
~1336 Kb 219 frames
stress.mpg For the same 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.
~790 Kb 219 frames
Constructing a Heap from a Line Source 
mid9f.mpg 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.
~1851 Kb 599 frames
Flow through a hopper 
funnel.mpg Now 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.
~2231 Kb 559 frames
funnel3.mpg Now the walls of the hopper are not as steep as in the previous example. The flow ends when an arch forms spontaneously and the hopper is blocked.
~2949 Kb 350 frames
funnel4.mpg Now we have the same geometry as in the previous example, but the shape of the particles was initialized slightly different. The hopper is not blocked anymore.
~2246 Kb 350 frames
funnel6.mpg Not quite a hopper, but a hole in the floor. 
~1886 Kb 300 frames
funnel5.mpg Now the slopes of the hopper are much steeper than in the previous examples. We see here the mass flow regime, where the particles pour through the outlet like in a liquid.
~1193 Kb 249 frames
funneltap.mpg The next 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.
~1192 Kb 219 frames
~10.0 MB


The different colors of the particles are used to visualize the movement of the particles.There is no difference in the physical parameters such as coefficent of friction or Young's modulus of the particles, only the shape varies.

©Alexander Schinner Last modified: 29/08/2001, 12.04