# Problem Definition
The problem is to simulate a double pedestal tote blender (mixer) with the diameter **0.03 m** and **0.1 m** respectively, the length **0.3 m**, rotating at **28 rpm**. This blender is filled with **24000** particles. The timestep for integration is **0.00001 s**. There is one type of particle in this blender. Particles are positioned before start of simulation to fill the blender.
* **24000** particles with **5 mm** diameter are positioned, in order, and let to be settled under gravity. After settling particles, this blender starts to rotate at t=**1s**.
a view of the tote-blender while rotating
particles are colored according to their velocity
# Setting up the Case
As it has been explained in the previous cases, the simulation case setup is based on text-based scripts. Here, the simulation case setup files are stored into two folders: `caseSetup`, `setting` (see the above folders). Unlike the previous cases, this case does not have the `stl` file and the surfaces are defined based on the built-in utilities in phasicFlow. See next the section for more information on how we can setup the geometry and its rotation.
## Geometry
### Defining rotation axis
In file `settings/geometryDict` the information of rotating axis and speed of rotation are defined. The rotation of this blender starts at time=**0.5 s** and ends at time=**9.5 s**.
```C++
// information for rotatingAxisMotion motion model
rotatingAxisMotionInfo
{
axisOfRotation
{
p1 (-0.1 0.0 0.15); // first point for the axis of rotation
p2 ( 0.1 0.0 0.15); // second point for the axis of rotation
omega 1.5708; // rotation speed ==> 15 rad/s
// Start time of Geometry Rotating (s)
startTime 0.5;
// End time of Geometry Rotating (s)
endTime 9.5;
}
}
```
### Surfaces
In `settings/geometryDict` file, the surfaces and motion component of each surface are defined to form a rotating tote-blender. The geometry is composed of top and bottom cylinders, top and bottom cones, a cylindrical shell and top and bottom Gates.
```C++
surfaces
{
topGate
{
// type of wall
type cylinderWall;
// begin point of cylinder axis
p1 (0.0 0.0 0.3);
// end point of cylinder axis
p2 (0.0 0.0 0.301);
// radius at p1
radius1 0.03;
// radius at p2
radius2 0.0001;
// material of wall
material solidProperty;
// motion component name
motion axisOfRotation;
}
topCylinder
{
// type of the wall
type cylinderWall;
// begin point of cylinder axis
p1 (0.0 0.0 0.28);
// end point of cylinder axis
p2 (0.0 0.0 0.3);
// radius at p1
radius1 0.03;
// radius at p2
radius2 0.03;
// number of divisions
resolution 36;
// material name of this wall
material solidProperty;
// motion component name
motion axisOfRotation;
}
coneShelltop
{
// type of the wall
type cylinderWall;
// begin point of cylinder axis
p1 (0.0 0.0 0.2);
// end point of cylinder axis
p2 (0.0 0.0 0.28);
// radius at p1
radius1 0.1;
// radius at p2
radius2 0.03;
// number of divisions
resolution 36;
// material name of this wall
material solidProperty;
// motion component name
motion axisOfRotation;
}
cylinderShell
{
// type of the wall
type cylinderWall;
// begin point of cylinder axis
p1 (0.0 0.0 0.1);
// end point of cylinder axis
p2 (0.0 0.0 0.2);
// radius at p1
radius1 0.1;
// radius at p2
radius2 0.1;
// number of divisions
resolution 36;
// material name of this wall
material solidProperty;
// motion component name
motion axisOfRotation;
}
coneShelldown
{
// type of the wall
type cylinderWall;
// begin point of cylinder axis
p1 (0.0 0.0 0.02);
// end point of cylinder axis
p2 (0.0 0.0 0.1);
// radius at p1
radius1 0.03;
// radius at p2
radius2 0.1;
// number of divisions
resolution 36;
// material name of this wall
material solidProperty;
// motion component name
motion axisOfRotation;
}
bottomCylinder
{
// type of the wall
type cylinderWall;
// begin point of cylinder axis
p1 (0.0 0.0 0.0);
// end point of cylinder axis
p2 (0.0 0.0 0.02);
// radius at p1
radius1 0.03;
// radius at p2
radius2 0.03;
// number of divisions
resolution 36;
// material name of this wall
material solidProperty;
// motion component name
motion axisOfRotation;
}
exitGate
{
// type of the wall
type cylinderWall;
// begin point of cylinder axis
p1 (0.0 0.0 -0.001);
// end point of cylinder axis
p2 (0.0 0.0 0.0);
// radius at p1
radius1 0.03;
// radius at p2
radius2 0.0001;
// number of divisions
resolution 36;
// material name of this wall
material solidProperty;
// motion component name
motion axisOfRotation;
}
}
```
## Defining particles
### Diameter and material of spheres
In the `caseSetup/sphereShape` the diameter and the material name of the particles are defined.
in caseSetup/sphereShape file
```C++
// name of shapes
names (sphere1);
// diameter of shapes (m)
diameters (0.005);
// material name for shapes
materials (solidProperty);
```
### Particle positioning before start of simulation
Particles are positioned before the start of simulation. The positioning can be ordered or random. Here we use ordered positioning. 24000 particles are positioned in a cylinderical region inside the tote-blender.
in settings/particlesDict file
```C++
// positions particles
positionParticles
{
// ordered positioning
method positionOrdered;
// maximum number of particles in the simulation
maxNumberOfParticles 25001;
// perform initial sorting based on morton code?
mortonSorting Yes;
// cylinderical region for positioning particles
cylinder
{
p1 (0.0 0.0 0.09);
p2 (0.0 0.0 0.21);
radius 0.09;
}
positionOrderedInfo
{
// minimum space between centers of particles
diameter 0.005;
// number of particles in the simulation
numPoints 24000;
// axis order for filling the space with particles
axisOrder (x y z);
}
}
```
## Interaction between particles
In `caseSetup/interaction` file, material names and properties and interaction parameters are defined. Since we are defining 1 material type in the simulation, the interaction matrix is 1x1 (interactions are symmetric).
```C++
// a list of materials names
materials (solidProperty);
// density of materials [kg/m3]
densities (1000.0);
contactListType sortedContactList;
model
{
contactForceModel nonLinearNonLimited;
rollingFrictionModel normal;
/*
Property (solidProperty-solidProperty);
*/
// Young modulus [Pa]
Yeff (1.0e6);
// Shear modulus [Pa]
Geff (0.8e6);
// Poisson's ratio [-]
nu (0.25);
// coefficient of normal restitution
en (0.7);
// coefficient of tangential restitution
et (1.0);
// dynamic friction
mu (0.3);
// rolling friction
mur (0.1);
}
```
# Performing Simulation and previewing the results
To perform simulations, enter the following commands one after another in the terminal.
Enter `$ particlesPhasicFlow` command to create the initial fields for particles.
Enter `$ geometryPhasicFlow` command to create the geometry.
At last, enter `$ sphereGranFlow` command to start the simulation.
After finishing the simulation, you can use `$ pFlowtoVTK` to convert the results into vtk format stored in ./VTK folder.
