CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > OpenFOAM > OpenFOAM Running, Solving & CFD

snappyhexmesh remove blockmesh geometry

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   March 19, 2014, 03:41
Default snappyhexmesh remove blockmesh geometry
  #1
New Member
 
Philipp Reinhold
Join Date: Nov 2013
Posts: 8
Rep Power: 12
philipp1 is on a distinguished road
Hi there,

i have a small question again. since i'm working just once per week on openfoam and snappyhexmesh, you've got to excuse, that these questions are sometimes a little bit stupid.

here we go:

i have created a geometry via snappyhexmesh, but the geometry or the faces from the blockmesh geometry do not seem to be removed. how do i do that? is this a setting in the snappyhexmeshdict?

Thank you,

PR
Attached Images
File Type: jpg bauteil1.jpg (97.5 KB, 152 views)
philipp1 is offline   Reply With Quote

Old   March 19, 2014, 05:39
Default
  #2
New Member
 
Philipp Reinhold
Join Date: Nov 2013
Posts: 8
Rep Power: 12
philipp1 is on a distinguished road
okay, i think i,ve got the right settings in the snappyhexmeshdict now, but i get a floating point exception now after 2 timesteps.. can anybody help me?
i have to finish this study in a few weeks

Quote:
Code:
Iteration 2
Moving mesh using displacement scaling : min:0.5625  max:0.5625
Checking faces in error :
    non-orthogonality >  65 degrees                        : 0
    faces with face pyramid volume < 1e-13                 : 6
    faces with face-decomposition tet quality < 1e-30      : 0
    faces with concavity >  80 degrees                     : 0
    faces with skewness >   4 (internal) or  20 (boundary) : 0
    faces with interpolation weights (0..1)  <  0.02       : 0
    faces with volume ratio of neighbour cells <  0.01     : 0
    faces with face twist <  0.02                          : 0
    faces on cells with determinant < 0.001                : 0

Iteration 3
Moving mesh using displacement scaling : min:0.421875  max:0.421875
Checking faces in error :
    non-orthogonality >  65 degrees                        : 0
    faces with face pyramid volume < 1e-13                 : 6
    faces with face-decomposition tet quality < 1e-30      : 0
    faces with concavity >  80 degrees                     : 0
    faces with skewness >   4 (internal) or  20 (boundary) : 0
    faces with interpolation weights (0..1)  <  0.02       : 0
    faces with volume ratio of neighbour cells <  0.01     : 0
    faces with face twist <  0.02                          : 0
    faces on cells with determinant < 0.001                : 0

Iteration 4
Moving mesh using displacement scaling : min:0.316406  max:0.316406
Checking faces in error :
    non-orthogonality >  65 degrees                        : 0
    faces with face pyramid volume < 1e-13                 : 6
    faces with face-decomposition tet quality < 1e-30      : 0
    faces with concavity >  80 degrees                     : 0
    faces with skewness >   4 (internal) or  20 (boundary) : 0
    faces with interpolation weights (0..1)  <  0.02       : 0
    faces with volume ratio of neighbour cells <  0.01     : 0
    faces with face twist <  0.02                          : 0
    faces on cells with determinant < 0.001                : 0

Iteration 5
Displacement scaling for error reduction set to 0.
Moving mesh using displacement scaling : min:0.237305  max:0.237305
Checking faces in error :
    non-orthogonality >  65 degrees                        : 0
    faces with face pyramid volume < 1e-13                 : 6
    faces with face-decomposition tet quality < 1e-30      : 0
    faces with concavity >  80 degrees                     : 0
    faces with skewness >   4 (internal) or  20 (boundary) : 0
    faces with interpolation weights (0..1)  <  0.02       : 0
    faces with volume ratio of neighbour cells <  0.01     : 0
    faces with face twist <  0.02                          : 0
    faces on cells with determinant < 0.001                : 0

Iteration 6
Moving mesh using displacement scaling : min:0  max:0
Checking faces in error :
    non-orthogonality >  65 degrees                        : 0
    faces with face pyramid volume < 1e-13                 : 0
    faces with face-decomposition tet quality < 1e-30      : 0
    faces with concavity >  80 degrees                     : 0
    faces with skewness >   4 (internal) or  20 (boundary) : 0
    faces with interpolation weights (0..1)  <  0.02       : 0
    faces with volume ratio of neighbour cells <  0.01     : 0
    faces with face twist <  0.02                          : 0
    faces on cells with determinant < 0.001                : 0
Successfully moved mesh
Moved mesh in = 0 s



Morph iteration 9
-----------------
Calculating patchDisplacement as distance to nearest surface point ...
Wanted displacement : average:0.000209065 min:0.000173982 max:0.000234267
Calculated surface displacement in = 0 s


Overriding displacement on features :
   implicit features    : false
   explicit features    : true
   multi-patch features : false

Stringing feature edges : changed 2 points
Stringing feature edges : changed 0 points
Attraction:
     linear   : max:(4.33681e-19 1.84314e-17 -0.000173982) avg:(5.42101e-20 5.50233e-18 -0.000209065)
     feature  : max:(0 1.47451e-17 0) avg:(-0.000360237 1.55854e-18 -6.80867e-05)
Feature analysis : total points:8 attraction to :
    feature point   : 0
    feature edge    : 4
    nearest surface : 0
    rest            : 4

--> FOAM Warning : Displacement (-0.000540986 -5.52943e-18 -9.83649e-05) at mesh point 0 coord (0.00108197 0.00190512 0.00019673) points through the surrounding patch faces
Smoothing displacement ...
Iteration 0
Iteration 10
Iteration 20
Displacement smoothed in = 0 s


Moving mesh ...

Iteration 0
Moving mesh using displacement scaling : min:1  max:1
Checking faces in error :
    non-orthogonality >  65 degrees                        : 0
    faces with face pyramid volume < 1e-13                 : 6
    faces with face-decomposition tet quality < 1e-30      : 0
    faces with concavity >  80 degrees                     : 0
    faces with skewness >   4 (internal) or  20 (boundary) : 0
    faces with interpolation weights (0..1)  <  0.02       : 0
    faces with volume ratio of neighbour cells <  0.01     : 0
    faces with face twist <  0.02                          : 0
    faces on cells with determinant < 0.001                : 0

Iteration 1
Moving mesh using displacement scaling : min:0.75  max:0.75
Checking faces in error :
    non-orthogonality >  65 degrees                        : 0
    faces with face pyramid volume < 1e-13                 : 6
    faces with face-decomposition tet quality < 1e-30      : 0
    faces with concavity >  80 degrees                     : 0
    faces with skewness >   4 (internal) or  20 (boundary) : 0
    faces with interpolation weights (0..1)  <  0.02       : 0
    faces with volume ratio of neighbour cells <  0.01     : 0
    faces with face twist <  0.02                          : 0
    faces on cells with determinant < 0.001                : 0

Iteration 2
Moving mesh using displacement scaling : min:0.5625  max:0.5625
Checking faces in error :
    non-orthogonality >  65 degrees                        : 0
    faces with face pyramid volume < 1e-13                 : 6
    faces with face-decomposition tet quality < 1e-30      : 0
    faces with concavity >  80 degrees                     : 0
    faces with skewness >   4 (internal) or  20 (boundary) : 0
    faces with interpolation weights (0..1)  <  0.02       : 0
    faces with volume ratio of neighbour cells <  0.01     : 0
    faces with face twist <  0.02                          : 0
    faces on cells with determinant < 0.001                : 0

Iteration 3
Moving mesh using displacement scaling : min:0.421875  max:0.421875
Checking faces in error :
    non-orthogonality >  65 degrees                        : 0
    faces with face pyramid volume < 1e-13                 : 6
    faces with face-decomposition tet quality < 1e-30      : 0
    faces with concavity >  80 degrees                     : 0
    faces with skewness >   4 (internal) or  20 (boundary) : 0
    faces with interpolation weights (0..1)  <  0.02       : 0
    faces with volume ratio of neighbour cells <  0.01     : 0
    faces with face twist <  0.02                          : 0
    faces on cells with determinant < 0.001                : 0

Iteration 4
Moving mesh using displacement scaling : min:0.316406  max:0.316406
Checking faces in error :
    non-orthogonality >  65 degrees                        : 0
    faces with face pyramid volume < 1e-13                 : 6
    faces with face-decomposition tet quality < 1e-30      : 0
    faces with concavity >  80 degrees                     : 0
    faces with skewness >   4 (internal) or  20 (boundary) : 0
    faces with interpolation weights (0..1)  <  0.02       : 0
    faces with volume ratio of neighbour cells <  0.01     : 0
    faces with face twist <  0.02                          : 0
    faces on cells with determinant < 0.001                : 0

Iteration 5
Displacement scaling for error reduction set to 0.
Moving mesh using displacement scaling : min:0.237305  max:0.237305
Checking faces in error :
    non-orthogonality >  65 degrees                        : 0
    faces with face pyramid volume < 1e-13                 : 6
    faces with face-decomposition tet quality < 1e-30      : 0
    faces with concavity >  80 degrees                     : 0
    faces with skewness >   4 (internal) or  20 (boundary) : 0
    faces with interpolation weights (0..1)  <  0.02       : 0
    faces with volume ratio of neighbour cells <  0.01     : 0
    faces with face twist <  0.02                          : 0
    faces on cells with determinant < 0.001                : 0

Iteration 6
Moving mesh using displacement scaling : min:0  max:0
Checking faces in error :
    non-orthogonality >  65 degrees                        : 0
    faces with face pyramid volume < 1e-13                 : 0
    faces with face-decomposition tet quality < 1e-30      : 0
    faces with concavity >  80 degrees                     : 0
    faces with skewness >   4 (internal) or  20 (boundary) : 0
    faces with interpolation weights (0..1)  <  0.02       : 0
    faces with volume ratio of neighbour cells <  0.01     : 0
    faces with face twist <  0.02                          : 0
    faces on cells with determinant < 0.001                : 0
Successfully moved mesh
Moved mesh in = 0 s


Repatching faces according to nearest surface ...
Repatched 0 faces in = 0 s


Edge intersection testing:
    Number of edges             : 6
    Number of edges to retest   : 6
    Number of intersected edges : 0
Merging 0 sets of faces.

No faces merged ...

Merging all points on surface that
- are used by only two boundary faces and
- make an angle with a cosine of more than 0.866025.

No straight edges simplified and no points removed ...
Snapped mesh : cells:1  faces:6  points:8
Cells per refinement level:
    0    0
    1    0
    2    0
    3    0
    4    0
    5    0
    6    1
Writing mesh to time 2
Wrote mesh in = 0 s.
Mesh snapped in = 0.05 s.
Layer thickness specified as final layer and expansion ratio.

Shrinking and layer addition phase
----------------------------------

Using mesh parameters 
{
    maxNonOrtho     65;
    maxBoundarySkewness 20;
    maxInternalSkewness 4;
    maxConcave      80;
    minVol          1e-13;
    minTetQuality   1e-30;
    minArea         -1;
    minTwist        0.02;
    minDeterminant  0.001;
    minFaceWeight   0.02;
    minVolRatio     0.01;
    minTriangleTwist -1;
    nSmoothScale    4;
    errorReduction  0.75;
}



Merging all faces of a cell
---------------------------
    - which are on the same patch
    - which make an angle < 60 degrees
      (cos:0.5)
    - as long as the resulting face doesn't become concave by more than 90 degrees
      (0=straight, 180=fully concave)

Merging 0 sets of faces.

No faces merged ...

Merging all points on surface that
- are used by only two boundary faces and
- make an angle with a cosine of more than 0.5.

No straight edges simplified and no points removed ...

Checking mesh manifoldness ...

Checking initial mesh ...
Checking faces in error :
    non-orthogonality >  65 degrees                        : 0
    faces with face pyramid volume < 1e-13                 : 0
    faces with face-decomposition tet quality < 1e-30      : 0
    faces with concavity >  80 degrees                     : 0
    faces with skewness >   4 (internal) or  20 (boundary) : 0
    faces with interpolation weights (0..1)  <  0.02       : 0
    faces with volume ratio of neighbour cells <  0.01     : 0
    faces with face twist <  0.02                          : 0
    faces on cells with determinant < 0.001                : 0
Detected 0 illegal faces (concave, zero area or negative cell pyramid volume)

Adding in total 0 inter-processor patches to handle extrusion of non-manifold processor boundaries.
Constructing mesh displacer ...

Handling points with inconsistent layer specification ...

Handling non-manifold points ...

Checking patch manifoldness ...
Outside of local patch is multiply connected across edges or points at 0 points.
Set displacement to zero for all 0 non-manifold points

Handling feature edges ...

Handling cells with warped patch faces ...
Set displacement to zero on 0 warped faces since layer would be > 0.5 of the size of the bounding box.

patch                            faces    layers avg thickness[m]
                                                 near-wall overall
-----                            -----    ------ --------- -------
lowerWall                        0        1      0         0       
runde_rueckfoerderstruktur_ascii 6        1      4.07e-06  4.07e-06

medialAxisSmoothingInfo : Calculate distance to Medial Axis ...
shrinkMeshDistance : Smoothing normals ...
    Iteration 0   residual 0.553
Inserting points on patch frontAndBack if angle to nearest layer patch > 30 degrees.
Inserting points on patch inlet if angle to nearest layer patch > 30 degrees.
Inserting points on patch outlet if angle to nearest layer patch > 30 degrees.
Inserting points on patch upperWall if angle to nearest layer patch > 30 degrees.
shrinkMeshDistance : Smoothing normals ...
shrinkMeshDistance : Smoothing normals in interior ...
    Iteration 0   residual 0.361

Layer addition iteration 0
--------------------------
Prevented extrusion on 0 coupled patch points during syncPatchDisplacement.

Determining displacement for added points according to pointNormal ...
No valid normal for point 0 (0.00108 0.00191 0.000197); setting displacement to (2.8e-06 -2.85e-06 7.59e-07)
No valid normal for point 4 (0.00108 0.00214 0.000197); setting displacement to (2.8e-06 2.85e-06 7.59e-07)
No valid normal for point 3 (0.0009 0.00191 0.000174); setting displacement to (-2.02e-06 -3.17e-06 1.55e-06)
No valid normal for point 5 (0.0009 0.00214 0.000174); setting displacement to (-2.02e-06 3.17e-06 1.55e-06)
Displacement at illegal point (0.00108 0.00191 0.000197) set to (-7.06e-05 8.69e-05 6.93e-06)
Displacement at illegal point (0.00108 0.00214 0.000197) set to (-9.51e-05 -5.7e-05 8.98e-06)
Displacement at illegal point (0.0009 0.00191 0.000174) set to (6.41e-05 0.000119 3.07e-05)
Displacement at illegal point (0.0009 0.00214 0.000174) set to (7.79e-05 -6.86e-05 4.12e-05)
Prevented extrusion on 0 coupled patch points during syncPatchDisplacement.

shrinkMeshMedialDistance : Smoothing using Medial Axis ...
#0  Foam::error::printStack(Foam::Ostream&) in "/opt/openfoam221/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#1  Foam::sigFpe::sigHandler(int) in "/opt/openfoam221/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#2   in "/lib/x86_64-linux-gnu/libc.so.6"
#3  Foam::autoLayerDriver::shrinkMeshMedialDistance(Foam::motionSmoother&, Foam::dictionary const&, Foam::List<Foam::Pair<int> > const&, int, double, int, int, double, Foam::Field<double> const&, Foam::Field<double> const&, Foam::GeometricField<Foam::Vector<double>, Foam::pointPatchField, Foam::pointMesh> const&, Foam::GeometricField<double, Foam::pointPatchField, Foam::pointMesh> const&, Foam::GeometricField<double, Foam::pointPatchField, Foam::pointMesh> const&, Foam::GeometricField<Foam::Vector<double>, Foam::pointPatchField, Foam::pointMesh> const&, Foam::List<Foam::autoLayerDriver::extrudeMode>&, Foam::Field<Foam::Vector<double> >&, Foam::List<int>&) const in "/opt/openfoam221/platforms/linux64GccDPOpt/lib/libautoMesh.so"
#4  Foam::autoLayerDriver::addLayers(Foam::layerParameters const&, Foam::dictionary const&, Foam::List<int> const&, int, Foam::decompositionMethod&, Foam::fvMeshDistribute&) in "/opt/openfoam221/platforms/linux64GccDPOpt/lib/libautoMesh.so"
#5  Foam::autoLayerDriver::doLayers(Foam::dictionary const&, Foam::dictionary const&, Foam::layerParameters const&, bool, Foam::decompositionMethod&, Foam::fvMeshDistribute&) in "/opt/openfoam221/platforms/linux64GccDPOpt/lib/libautoMesh.so"
#6  
 in "/opt/openfoam221/platforms/linux64GccDPOpt/bin/snappyHexMesh"
#7  __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6"
#8  
 in "/opt/openfoam221/platforms/linux64GccDPOpt/bin/snappyHexMesh"
thank you
philipp1 is offline   Reply With Quote

Old   December 12, 2014, 11:58
Default
  #3
Member
 
Petr Furmanek
Join Date: Jan 2012
Location: Faenza, Italy
Posts: 66
Rep Power: 14
petr.f. is on a distinguished road
Hi Philipp,

I'm constantly facing very similar problem - snappy blows out during layer addition phase when moving mesh using displacement scaling. Usually I get something like

Moving mesh using displacement scaling : min:0.5625 max:1
[3] #0 Foam::error:rintStack(Foam::Ostream&) in "/opt/OpenFOAM/OpenFOAM-2.3.x/platforms/linux64Gcc48DPOpt/lib/libOpenFOAM.so"
[3] #1 Foam::sigFpe::sigHandler(int) in "/opt/OpenFOAM/OpenFOAM-2.3.x/platforms/linux64Gcc48DPOpt/lib/libOpenFOAM.so"
[3] #2
[3] at sigaction.c:0
...

So far the only thing that helped me was:
1) using different snappyHexMeshDict for snap and addLayers phases,
2) decreasing the featureAngle and/or
3) increasing number of smoothing iterations, e.g.
nSmoothSurfaceNormals 50;
nSmoothNormals 30;
nSmoothThickness 50;
4) AND increasing the error reduction e.g.
errorReduction 0.9;

Good luck.
petr.f. is offline   Reply With Quote

Reply

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
[blockMesh] blockmesh arc, no curves, no arc, only straight lines heavy_user OpenFOAM Meshing & Mesh Conversion 9 January 26, 2017 21:48
[snappyHexMesh] Incomplete geometry in snappyHexMesh anon_a OpenFOAM Meshing & Mesh Conversion 2 March 12, 2012 05:30
[snappyHexMesh] Cannot get my geometry file inside the blockMesh lovecraft22 OpenFOAM Meshing & Mesh Conversion 6 March 3, 2012 12:22
[DesignModeler] Error while Loading a Geometry JD944 ANSYS Meshing & Geometry 0 October 25, 2011 15:51
[Gmsh] Problem meshing an imported geometry Alicia OpenFOAM Meshing & Mesh Conversion 0 March 30, 2010 05:53


All times are GMT -4. The time now is 02:53.