CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > OpenFOAM > OpenFOAM Meshing & Mesh Conversion

[snappyHexMesh] Resolving Trailing Edges of Airfoil in sHM

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   September 15, 2019, 15:18
Default Resolving Trailing Edges of Airfoil in sHM
  #1
New Member
 
Stefan
Join Date: Dec 2016
Posts: 5
Rep Power: 5
sfluck is on a distinguished road
Hi there

I am trying to make a mesh with snappyHexMesh for a multi element airfoil chord 37 cm). I have the airfoil as an stl with three named regions (slat, main, flap).

I struggle mainly with resolving the trailing edges nicely with at least 1 adjacent cell, my inflation layers keep collapsing at the trailing edge. The trailing edges are cut to a width of about 0.5 mm. All feature edges are extracted with surfaceFeatures (OF V7), the generated obj of the feature edges shows that clearly. Attached are some images of the problem areas. The trailing edge cuts of the stl geometry are about perpendicular to the form, not as crooked as they appear in the mesh.
SnappyHexMeshDict can be found here: www.pastebin.com/63CMVxqq

I managed to do a case with pointy trailing edges (uncut) with a mere 4 and relatively thick inflation layers that wrap nicely around the trailing edge, but y+ values are too high like that. Making the layers thinner makes them collapse again, also increasing the refinement leads to a collapsing boundary layer. I played around with tolerances, feature snapping parameters, featureAngle, nothing seems to help, I started to get a bit annoyed. Especially because I don't really know what some parameters mean and don't find the documentation to be really helpful.

What are the parameters that steer the "wrapping-around-corner"-behavior in the sHMDict? Where would you start tuning? On my 8-core pc generating a new mesh takes (depending on n<...>Iterations) about 5-10minutes for castellated, snapping and addLayer-Phases. I've been playing around for about a week now trying different settings, good thing I'm a student and "free" workforce :-).

Also, my base mesh is generated with blockMesh, and it's quite coarse. I figured the refinementRegions in the sHM are enough to break the base mesh down a bit for surface snapping. The snapping step seems to work neatly though, except for the trailing edge snapping. Shouldn't
surfaceFeatures do the trick there?

Any help is appreciated! It's probably not that hard of a problem, I just seem to not see the solution anymore.

Kind wishes
Stefan
Attached Images
File Type: jpg Anmerkung 2019-09-15 195636.jpg (121.9 KB, 24 views)
File Type: jpg Anmerkung 2019-09-15 195703.jpg (107.1 KB, 26 views)
sfluck is offline   Reply With Quote

Old   September 16, 2019, 02:51
Default
  #2
Senior Member
 
linnemann's Avatar
 
Niels Nielsen
Join Date: Mar 2009
Location: NJ - Denmark
Posts: 518
Rep Power: 22
linnemann will become famous soon enough
This will be very difficult to obtain.

I would advice you to test out cfMesh.
It does a lot better in taking proper care of layers like this.
__________________
Linnemann

PS. I do not do personal support, so please post in the forums.
linnemann is offline   Reply With Quote

Old   September 16, 2019, 14:35
Default
  #3
New Member
 
Stefan
Join Date: Dec 2016
Posts: 5
Rep Power: 5
sfluck is on a distinguished road
Thanks, I'll look into it.
sfluck is offline   Reply With Quote

Reply

Tags
addlayercontrols, parameters, snappyhesmeshdict

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Ffd_control_point_2d feiyi SU2 4 September 30, 2019 13:42
How to deal with prism layers in sharp trailing edge of the airfoil Rinia STAR-CCM+ 1 March 11, 2019 21:25
[snappyHexMesh] Error snappyhexmesh - Multiple outside loops avinashjagdale OpenFOAM Meshing & Mesh Conversion 53 March 8, 2019 10:42
[snappyHexMesh] No layers in a small gap bobburnquist OpenFOAM Meshing & Mesh Conversion 6 August 26, 2015 10:38
Boundary layer meshing with sharp trailing edges Andrew Berner FLUENT 1 August 28, 2007 18:39


All times are GMT -4. The time now is 07:53.