|
[Sponsors] |
[cfMesh] question increasing layer quality on concave surfaces |
|
LinkBack | Thread Tools | Search this Thread | Display Modes |
February 19, 2024, 10:54 |
question increasing layer quality on concave surfaces
|
#1 |
New Member
Georg Göbel
Join Date: Sep 2016
Location: Karlsruhe
Posts: 8
Rep Power: 10 |
Dear cfMesh users and developers,
i am currently meshing a inland waterway ship with the goal of representing y+<1 which leads to a first layer thickness in the area of 0.00005 m. I am going for ~15 layers and a thicknessRatio of 1.2. The size of the finished mesh is around 25 mio cells. The ships geometrie is not overly complicated but still offers some concave two dimensional curvature on the bow and aft. In this area i create really bad shaped layer cells which make the simulations crash. On the less complex areas the mesh is perfectly fine. I attached two pictures which show a slice before and after layer generation. It is visible that the cartesian cells are allready diagonally cut and include some bad shaped cells before layer generation. After layer generation, the mesh is completely crooked and some points are even pentrating the boundary. I experimented with surfaceFeatureExtract -angle and found, that it gets slightly better for higher angles, but that only means that i get 50k badCells instead of 60k badCells. Does anyone know a way to solve or workaround this problem? Could this be solved with a better .stl representation? I am grateful for every reply! Georg |
|
August 1, 2024, 11:07 |
|
#2 |
Member
Lourenço SM
Join Date: Jul 2014
Location: Lisboa, Portugal
Posts: 41
Rep Power: 12 |
1-Visualize cells better in Paraview, choosing "crinkle" in the filter settings.
2-In snappyHexMesh/layers, use relativeSizes=False 3-In snappyHexMesh/layers, try nLayerIter > 1, up to 20, or more (you want too many layers) Check this tips: https://cfdmonkey.com/tips-and-trick...snappyhexmesh/ https://cfdmonkey.com/snappyhexmesh/ Else, try swiftBlock alone or combined with snappyHexMesh. Good luck! |
|
October 9, 2024, 07:32 |
|
#3 |
New Member
Skill-Lync CFD
Join Date: Sep 2024
Location: Chennai
Posts: 16
Rep Power: 2 |
Few things you can do:
1. Use feature edge refinement 2. Turn relative sizing off, give layer thickness appropriately 3. Use "surfaceFeatureEdges -angle *insert angle here* " to divide your STL into sharp edges, so you can refine each feature appropriately. > For your case it would seem 90 degrees would be a good choice. |
|
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
[snappyHexMesh] No generation of layer onto zerothickness surface | crubio.abujas | OpenFOAM Meshing & Mesh Conversion | 3 | October 25, 2022 03:20 |
[snappyHexMesh] How to refine geometry only near small regions? | joshmccraney | OpenFOAM Meshing & Mesh Conversion | 2 | September 2, 2022 08:22 |
[snappyHexMesh] SHM Bad quality snapping/terracing | ryan55510 | OpenFOAM Meshing & Mesh Conversion | 0 | April 20, 2022 20:20 |
SHM layer problem on inside mesh | boffin5 | OpenFOAM Running, Solving & CFD | 1 | November 20, 2021 06:26 |
[snappyHexMesh] Boundary layer generation problems | ivan_cozza | OpenFOAM Meshing & Mesh Conversion | 0 | October 6, 2010 13:47 |