Defining Lagrangian Phases

A Lagrangian phase is used to define the solid particles in the simulation. The phase requires specific physics models and properties to characterize its behavior. In this case, the solid particles are grains of wheat, with the material properties defined manually.

To define the Lagrangian phase:
  1. Right-click the Lagrangian Multiphase > Lagrangian Phases manager and select New > Free-stream Phase.
  2. Rename the phase as Grain.
  3. Right-click the Grain > Models manager and select Select models.
  4. In the Grain Model Selection dialog, select the following models, in order:
    Group Box Model
    Particle Type DEM Particles
    Optional Particle Forces Pressure Gradient Force (selected automatically)
    Material Solid
    Equation of State Constant Density
    Particle Shape Composite Particles
  5. Click Close.

To define the material properties for the Grain particles:

  1. Select Models > Solid > Rubber and rename the Rubber node to Wheat.
  2. Select the Material Properties > Density > Constant node and set the Value to 700 kg/m^3.
  3. Set the remaining properties as follows:
    Property Setting
    Poisson's Ratio 0.5
    Young’s Modulus 0.2 MPa

To define the physical shape of the grain particles:

  1. Right-click the Model > Composite Particles > Shapes node and select New.
  2. Select the Sphere 1 node and set the Radius to 0.8.
  3. Create two more shapes with the following properties:
    Node Property Setting
    Sphere 2 Position [1.0, 0.0, 0.0]
    Radius 1.0
    Sphere 3 Position [2.0, 0.0, 0.0]
    Radius 0.8
  4. Right-click the Composite Particles node and select Show model.
A representation of the grain particle is shown in the Graphics window.

  1. Close the Composite particle Grain scene.

To define the physics conditions on the particle boundary:

  1. Right-click the Grain > Boundary Conditions > Wall > Physics Conditions > Boundary Properties > Solid > Al node and select Replace with.
  2. In the Replace Material dialog, expand the Material Databases > Standard > Solids manager, select Rubber (Arlon Thermabond 99180T010) and click OK.
  3. Select the Physics Conditions > Mode node and check that the Active Mode property is set to DEM mode.
  4. Save the simulation.