The first two simulations are 196 particles. Parameters are restitution .8, friction .2, radius 2mm, drum radius is 3cm. Rotation rate is 2*pi radians per second.

Pictures are every second corresponding to one complete rotation Click here 800KB These pictures are every 0.04 seconds for the first 10 seconds Click here 2MB

The next two are increasing the radius by two to 6cm. To keep the relative gravitational force the same the rotation rate is halved to pi radians per second. The number of particles is 784. These pictures are every 0.04 seconds for the first 10 seconds Click here 1.3MB These pictures are every 2 seconds (one complete rotation) for the first 100 seconds Click here 2MB

This simulation is a segregation experiment with 400 particles of radius 4mm and 8mm, half of each randomly chosen. A snapshot of the final state is here

The second has 250 particle all of radius 8mm. There are snapshots at the start and at the end. A Picture with two graphs showing the individual particle motion form rotation to rotation are here The mean rotation has been subtracted off.

The third is the same as the second but g = cos(38/180*pi)*9.81 = 7.7304. There are snapshots at the start and at the end. A Picture with two graphs showing the individual particle motion form rotation to rotation are here The mean rotation has been subtracted off. The particle movement is noticeably different in particular the average angular velocity, over and above the drum angular velocity, is twice as large.

Cylinder is rotating with angular velocity 2*pi=60rpm. Cylinder radius 15cm. For one and two g is 9.81. For 3 g is cos(38/180*pi)*9.81 = 7.7304. Particle-particle and particle-wall friction are 0.2. Particle-particle and particle-wall restitution are 0.8. Mass and moment of inertia are chosen for 2d particles that is M = rho*r^2 and MI = .5*M. Three more rotating drum simulations a , b, c.

200 balls

2000 balls

6325 balls

avalanche inside a large drum

Jim McElwaine Last modified: Wed Jul 15 17:21:23 JST 1998