Vicous layer on sharp corners

[gcayser]

I have been working on Salome with this geometry in order to test the behaviour of viscous layer creation on sharp corners. The issue I am having is that the transition on these corners is simply too abrupt, as can be seen in the following image:

The mesh I am generating on Salome is then being compared to ANSA, and I am trying to find a way in which I can make the corner transition smoother. In ANSA, this fucntion is called “Smooth normal vectors”, but I cannot seem to find anything in Salome that does the same. Does anyone know of a workaround?

Thank you in advance.

[franco.ota]

have you tested the surface offset+smooth on the viscous layers?

[gcayser]

Hey, thanks for your reply. I tried the other methods but they give me the same result. I am mainly interested in the node offset, as it works better for my specific application. The parameters I used are the following:

Mesh_1 (Domain – FF/SYMMETRY):

• Algorithm: NETGEN 1D-2D-3D

• Hypothesis: NETGEN 3D Parameters

  • Max size: 1000
  • Min size: 10
  • Fineness: Moderate

• Viscous layer:

  • Total thickness: 111.3
  • Number of layers: 53
  • Stretch factor: 1.2
  • Extrusion method: Node offset
  • Specified faces are: Faces with layers (walls)
  • Faces with layers (walls): “WALL” group

• Sub-mesh_1 (Geometry – WALL)

  • Algorithm: NETGEN 1D-2D
  • Hypothesis: NETGEN 2D Parameters
    • Max size: 25
    • Min size: 1
    • Moderate

The geometry has 800mm in length.

I need it to look something like this:

[clef1]

Hello everyone,

I have the same problem. I try to create a 2D psedo mesh for OpenFOAM (3D mesh with only one cell in the z direction). So, I first create a 2D mesh and then extrude it at one cell on the z direction.

However, when I use Viscous layer, I have a similar problem with gcayser (see screenshot below).

I used step file from Rhino to import the geometry and I grouped the four edges of the square in Geometry section.

I think the solution is somehow to “group” the four edges.

Any ideas?

Thank you,

[franco.ota]

first would say that you need to share your geometry. there might be something wrong with it.

example.py (2,3 KB)

[clef1]

Good day dear,

You are right, I should attach.

You may find attached here the file that contains geometry and 2D meshing.

I also attach the step file I used to import geometry.

Further more, I would like to ask, is python with salome worth giving a try?

Thank you,
Chris

square_2D_V1.hdf (3.9 MB)
square.stp (8.0 KB)

[franco.ota]

Further more, I would like to ask, is python with salome worth giving a try?

clearly.
sadly in my current PC I can not use salome as I am having issues with. will check later, but run the pyhon script to check what I did. and guide you from that

[clef1]

Thank you Franco,

I will wait for your response after you check it.
I will surely check the python scripts as I am familiar with python in general (not in salome yet)

[clef1]

Dear Franco,

I have examined your file and tried to follow the steps you took for the generation. However, beacause I need higher resolution on near wall edges, I increased the number of segments on edges through python. This resulted to the undesired result on the vertices (see image below).

I also atatch the .py file, which only differes in th number of segments (you used 10, I used 100)

Salome_example.py (2.3 KB)

Thank you,
Chirs

[franco.ota]

can confirm that thats not the expected behavior…
I also tried to hackish solve it by doing a 3D mesh, (as the BL addition in 3D has some extra possibilities that the 2D does not have) but same result.