Dynamic Mesh – Moving Cell Zone

Introduction

This is a simple example of the Moving Cell Zone feature within the Dynamic Mesh function. It describes a motion where the pitch angle of each rotor changes as the two rotors rotate. There is a single cell zone surrounding the entire rotor, and inside it, there are two cell zones surrounding each rotor. The outer cell zone undergoes rotational motion, while the rotor pitch angle undergoes periodic rotation in the opposite direction relative to the rotor axis.

In this example, we only check the movement of the grid without calculating the flow field.

Start BaramFlow and load mesh

Run the program and select [New Case] from the launcher. In the launcher, select [Pressure-based] for [Solver Type] and [Volume of Fluid] for [None].

Use the given polyMesh folder. In the menu, click [File]-[Load Mesh]-[OpenFOAM] and select the polyMesh folder.

General

Change Time to Transient. Use default conditions for the rest.

Models

All use default conditions.

Materials

Use the default air as is.

Cell zone Conditions

Use the default conditions as they are.

Boundary Conditions

Set the boundary conditions of the two rotating rotors, cube_surface and cube1_surface, to Wall – Moving Wall – Mesh Motion.

Dynamic Mesh

Specify the grid motion. Set the Motion Type to Moving Cell Zone.

Assign the motion of each of the three cell zones to Motion Definitions.

Motion-1 : Motion of the outer cell zone
- Motion Functions : Rotation
  - Origin : (0 0 0)
  - Axis : (0 0 1)
  - Speed : 20
- CellZones : Cylinder_3

Motion-2 : Motion of the first rotor – Specifies two motions: rotation and change in pitch angle.
- Motion Functions
  - Rotation
    - Origin : (0 0 0)
    - Axis : (0 0 1)
    - Speed : 20
  - Rotating Oscillation
    - Origin : (0 0 0)
    - Amplitude : (-45 0 0)
    - Speed : 20
- CellZones : Cylinder_1

Motion-3 : Motion of the second rotor – Specifies two motions: rotation and change in pitch angle.
- Motion Functions
  - Rotation
    - Origin : (0 0 0)
    - Axis : (0 0 1)
    - Speed : 20
  - Rotating Oscillation
    - Origin : (0 0 0)
    - Amplitude : (45 0 0)
    - Speed : 20
- CellZones : Cylinder_2