DynamicMesh – Moving Boundary
Introduction
This is a simple example of the Moving Boundary feature in the Dynamic Mesh function. It is a process in which a cube inside a duct moves in the z-direction at a speed of -0.1 m/s, causing the flow path to narrow.
In this example, we only check the mesh motion 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
Each boundary condition is set as follows.
- Hex6_1_xMin : Velocity Inlet
- Velocity Magnitude : 1
- Hex6_1_xMax : Pressure Outlet
- Pressure : 0
- Hex6_1_yMin, Hex6_1_yMax : Symmetry
- Hex6_1_zMin, Hex6_1_zMax, : Wall
- Wall Motion : Stationary Wall
- Hex6_2_xMin, Hex6_2_xMax, Hex6_2_zMin : Wall
- Wall Motion : Moving Wall – Mesh Motion
Dynamic Mesh
Specify the mesh motion. Set the Motion Type to Moving Boundary.
The conditions for Boundaries are set as follows.
Hex6_2_zMin : Prescribed Motion – Linear Translation – (0 0 -0.1)
Hex6_2_xMin, Hex6_2_xMax : Slip
Hex6_1_xMin, Hex6_1_xMax, Hex6_1_zMin, Hex6_1_zMax : Fixed
Hex6_1_yMin, Hex6_1_yMax : Symmetry
Numerical Conditions
First, disable flow calculations to check only the mesh motion. Press the Advanced button and disable Flow in Equations.
Set Max. Iteration per Time Step to 1.
The rest all use default values.
Initialization
Use default conditions.
Run
[Run Conditions] are set as follows.
- Time Stepping Method : Adaptive
- Courant Number : 1
- End Time : 2
- Save Interval : 0.05
Click the [File]-[Save] button in the menu to save.
Post-processing
Run ParaView by clicking the [External tools]-[ParaView] in the menu.
If it is a parallel operation, change [Case Type] to [Decomposed Case].
Disable the [Skip Zero Time] option.
Change [Representation] to [Surface With Edges].
Set the View Point to +y and change the Coloring to Solid or PointDisplacement.
You can check the mesh motion by pressing the Play icon.
