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

[snappyHexMesh] help to troubleshooting snappy mesh errors

Register Blogs Community New Posts Updated Threads Search

 
 
LinkBack Thread Tools Search this Thread Display Modes
Prev Previous Post   Next Post Next
Old   June 9, 2020, 10:10
Default help to troubleshooting snappy mesh errors
  #1
Senior Member
 
Franco
Join Date: Nov 2019
Location: Compiègne, France
Posts: 129
Rep Power: 6
otaolafr is on a distinguished road
hello,
I am trying to use snappyHexMesh with a complex geometry,
it has really small volumes, in some parts (see figures attached).
the surface mesh i prepeared with salome from the STEP file.
the background mesh i am creating it with blockMesh function,
my issue is that when doing snappy, it gets a lot of illegal faces in the morphing phase (only faces with face pyramid volume < 1e-13: 30842824 ), so snappy keeps trying to solve this problem and the morphing phase iterations begins, until the morph iteration 10 the illegal faces stay the same, and after, the face with face pyramid volume < 1e-13 begins to decrease, other errors begins to appear .... ( first non-orthogonality > 65 degrees that increas in number until morph 22 then faces with face-decomposition tet quality < 1e-15 and faces with face twist < 0.02 appears). after this i beging getting foam warnings:
Code:
From function static Foam::vectorField Foam::snappySnapDriver::calcNearestSurface(const Foam::meshRefinement&, const scalarField&, const indirectPrimitivePatch&, Foam::pointField&, Foam::vectorField&)
    in file snappyHexMeshDriver/snappySnapDriver.C at line 1638
several times each morph iteration and at the end i finish with:
Code:
    non-orthogonality > 65  degrees                        : 8904
    faces with face pyramid volume < 1e-13                 : 30833798
    faces with face-decomposition tet quality < 1e-15      : 41
    faces with concavity > 80  degrees                     : 3
    faces with skewness > 4   (internal) or 20  (boundary) : 1
    faces with interpolation weights (0..1)  < 0.05        : 1
    faces with volume ratio of neighbour cells < 0.01      : 0
    faces with face twist < 0.02                           : 5
    faces on cells with determinant < 0.001                : 4
Finished meshing with 30842757 illegal faces (concave, zero area or negative cell pyramid volume)
I was looking any guideline or troubleshooting to read so i can improve my snappydict or my background mesh, as i have found several tutorials for snappy but where this problem does not show.
I do not know where to beging as there is so much features in snappy, and as it takes some time to run (17000secs) I can not change easyly the parameters and re run it...
I am attaching the blockMeshDict and also the snnapy and the log.snappy if it helps.
i also attach the photos of the surface mesh , how it looks inside, and also the edges i capture from the surfaceFeatureExtract (i can say that it is extracting the correct edges....)

best regards,
franco
Attached Images
File Type: jpg image51.jpg (26.7 KB, 53 views)
Attached Files
File Type: txt blockMeshDict.txt (3.4 KB, 6 views)
File Type: txt snappyHexMeshDict.txt (9.5 KB, 10 views)
File Type: txt log.snappyHexMesh.txt (135.7 KB, 5 views)
otaolafr is offline   Reply With Quote

 


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
[snappyHexMesh] Snappy Hex Mesh - issue with smoothness of the model edges olek.warc OpenFOAM Meshing & Mesh Conversion 1 August 31, 2018 11:31
Unstructrued O-type Mesh of a cylinder with icoFoam kindle OpenFOAM Running, Solving & CFD 1 December 2, 2016 11:45
Floating point exception error lpz_michele OpenFOAM Running, Solving & CFD 53 October 19, 2015 02:50
AMI interDyMFoam for mixer nu problem danny123 OpenFOAM Programming & Development 8 September 6, 2013 02:34
Icemcfd 11: Loss of mesh from surface mesh option? Joe CFX 2 March 26, 2007 18:10


All times are GMT -4. The time now is 08:17.