Cavity
Introduction
- This example is an example of mesh generation for a three-dimensional transonic cavity flow analysis.
- The cavity model is inside a wind tunnel and is the geometry from the following paper.
Numerical Simulation of High-Speed Turbulent Cavity Flows, G.N.Barakos, S.J.Lawson, R.Steijil, P.Nayyar, Flow Turbulence Combust, 2009
Geometry
Use given 7 stl files as geometry.
Click the [Import] button at the bottom to select the stl files.
It consists of a cavity model and six surfaces of a farfield boundary. Rename the volume to Cavity. Right-click and select [Edit/View] to rename the faces as follows.
- Visualization_Toolkit_generated_SLA_file_surface : right
- Visualization_Toolkit_generated_SLA_file_surface1 : forward
- Visualization_Toolkit_generated_SLA_file_surface2 : down
- Visualization_Toolkit_generated_SLA_file_surface3 : left
- Visualization_Toolkit_generated_SLA_file_surface4 : up
- Visualization_Toolkit_generated_SLA_file_surface5 : wall
- Visualization_Toolkit_generated_SLA_file_surface6 : back
Create a hexahedron in the area where you want to create a dense mesh. Create two hexahedra in the cavity and near the walls of the model as follows.
Click the [Add] button and select [Hex] and set values as follows
- Name : Hex_1
- Type : None
- MIn. : (1.75 1.1 -0.2)
- Max. : (2.5 1.3 0.1)
In Geometry, select Hex_1_surface and right-click and select Edit/View. In the window that opens, change the type as [None].
Once more, click the [Add] button and select [Hex] and set values as follows
- Name : Hex_2
- Type : None
- MIn. : (1 1 0)
- Max. : (3 1.5 0.05)
In Geometry, select Hex_2_surface and right-click and select Edit/View. In the window that opens, change the type as [None].
Click the [Next] button to move on to the next step.
Region
Click the (+) icon at the top to create a region. Move the mouse to the intersection of the lines that appear in light green color in the graphics window and position it inside the computation domain. Click the [Add] button to complete the setup.
Click the [Next] button to move on to the next step.
Base Grid
Set the number of grids to 36, 24, and 26. Click the [Generate] button to generate the base grid.
Click the [Next] button to move on to the next step.
Castellation
Surface/Feature Refinement
Click the (+) icon under [Surface/Feature Refinement] and set the following settings
- Surface Refinement
- Minimum Level : 2
- Maximum Level : 2
- Feature Edge refinement Level : 2
- Surfaces : wall
Volume Refinement
Click the (+) icon under [Volume Refinement] and set the following settings
- Volume Refinement Level : 5
- Volume : Hex_1
Once more, click the (+) icon under [Volume Refinement] and set the following settings
- Volume Refinement Level : 4
- Volume : Hex_2
Click the [Refine] button and the castellation step starts.
The result looks like this
Click the [Next] button to move on to the next step.
Snap
Change the [Feature Snap Type] under [Feature Snapping] to [implicit] and click the [Snap] button to start snap.
Click the [Next] button to move on to the next step.
Boundary Layer
Click the (+) icon under [Configuration] to add a [Setting], and set it as follows
- Number of Layers : 5
- Thickness Model Specification : First and Expansion
- Size Specification : Relative
- First Layer Thickness : 0.1
- Expansion Ratio : 1.2
- Min. Total Thickness : 0.3
- Boundary : wall
Use default values for [Advanced] Configuration.
Click [Apply] button to start boundary layer step.
The final mesh looks like this
Click the [Next] button to move on to the next step.
Export
Click [Export as BaramFlow project] to export the mesh to the desired location.