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Gap Refinement

Download geometry file

Download BaramMesh folder

Introduction

This example is to help you understand the function of [Gap Refinement] added in BARAM-v24.2.

Gap Refinement has the following inputs and options: [Min. Cell Layers in a gap], [Gap Detection Start Level], [Max. Refinement Level], [Direction], and [Include surface's own gap]. Let's see how the mesh is generated based on these settings.

Geometry

Use given hex_with_self_gap.stl file, a sphere and a hexahedron as geometry.

Click the [Import] button at the bottom to select the hex_with_self_gap.stl file.


Create sphere and hexahedron

  • Sphere : Click [Add] button and in new window select [Sphere]
    • Center point : (0 6.5 0)
    • Raidus : 2.


  • Hexahedron : Click [Add] button and in new window select [Hex].
    • Min. : (-9 9 -2)
    • Max. : (10 9.5 2)


  • Outer boundary(Hex6) : Click [Add] button and in new window select [Hex8]
    • Min. : (-20 -10 -5)
    • Max. : (20 16 5)



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

Select [Use Hex6] option and set the number of grids to 20, 13, and 5. Click the [Generate] button to generate the base grid.


Click the [Next] button to move on to the next step.

Castellation

Click the (+) icon under [Volume Refinement] and set the following settings

  • Volume Refinement Level : 1
  • Gap Refinement
    • Min. Cell Layers in a gap : 4
    • Gap Detection Start Level : 1
    • Max. Refinement Level : 4
    • Direction : Mixed
    • Include surface's own gap : On
  • Volume : Hex6_1

The idea is that any area smaller than [Gap Detection Start Level] (in this case, 1) is considered a [gap] and must contain at least 4 grids. The [Max. Refinement Level] is given as 4, so even if the level is 4 and it doesn't fit more than 4, it doesn't refine any more. The direction is both inward and outward, and includes gaps caused by surface's own side.


Use the default settings, 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] of [Feature Snapping] to [implicit] and click the [Snap] button to start snap.

Effects of Gap Refinement settings

Try creating a mesh by changing the input variables and options for Gap Refinement.

Effect of [Gap Detection Start Level]

If we change [Gap Detection Start Level] to 2, the result is as follows

Because the size of the gap is greater than size level 2, no refinement is done.

Effect of [Direction]

If we change [Direction] to inside and outside, the result is as follows.

Effect of [Include surface's own gap]

The impact of this option is as follows