The problem is to simulate a rotating drum with the diameter **0.24 m**, the length **0.1 m** and **6** Baffles, rotating at **15 rpm**. This drum is filled with **20000** Particles.The timestep for integration is **0.00001 s**. There are 2 types of Particles in this drum each are beining inserted during simulation to fill the drum.
* **12500** Particles with **4 mm** diameter, at the rate of 12500 particles/s for 1 sec.
* **7500** Particles with **5mm** diameter, at the rate of 7500 particles/s for 1 sec.
As it has been explained in the previous cases, the simulation case setup is based on text-based scripts. Here, the simulation case setup are sotred in three folders: `caseSetup`, `setting` and `stl` (see the above folders).
## Defining small and large particles
Then in the `caseSetup/sphereShape` the diameter and the material name of the particles are defined. Two sizes are defined: 4 and 5 mm.
In this case we have two region for inserting our particles. In the both region we define rate of insertion, start and end time of insertion, information for the volume of the space throught which particles are being inserted. The insertion phase in the simulation is performed between times 0 and 1 seconds.
For example, for the insertion region for inserting light particles is shown below.
In `caseSetup/interaction` file, material names and properties and interaction parameters are defined: interaction between the particles and the shell of rotating drum. Since we are defining 3 materials for simulation, the interaction matrix is 3x3, while we are only required to enter upper-triangle elements (interactions are symetric).
In the `settings/geometryDict` file, the geometry and axis of rotation is defined for the drum. The geometry is composed of a body, front and rear ends.
In this part of `geometryDict` the information of rotating axis and speed of rotation are defined. The start of rotation is at 2 s. The first 2 seconds of simulation is for allowing particles to settle donw in the drum.