OpenFOAM® v1806: Notable bug-fixes
snappyHexMesh layer feature angle
This is a pure bug fix and not a feature extension. It might affect your snappyHexMesh meshes. In v1712 and earlier the featureAngle setting in the layer controls section of the snappyHexMeshDict
addLayersControls
{
// When not to extrude surface. 0 is flat surface,
// 90 is when two faces are perpendicular. Note that this
// is the angle of the mesh surface (so after snapping) and not
// the original geometry.
featureAngle 130;
}
was not interpreted correctly (it was missing a degrees-to-radians conversion). Consequently in v1712 any setting greater than 60 degrees would disable all layer extrusion.
In below figures the effect (in v1806) of two feature angles is shown:
- 45 degrees i.e. disabling all extrusion in sharp angles
- 130 degrees, i.e. allowing extrusion in sharp angles)
Note: some default values of parameters are calculated from above featureAngle setting. These parameters are:
//mergePatchFacesAngle 45;
// Do not extrude around sharp edge if not both faces are extruded.
// Default is 0.5*featureAngle. Set to -180 always attempt extrusion
//layerTerminationAngle -180;
// Optional: at non-patched sides allow mesh to slip if extrusion
// direction makes angle larger than slipFeatureAngle. Default is
// 0.5*featureAngle.
//slipFeatureAngle 30;
Hence if you change the featureAngle parameter in v1806 and would like to get exactly the same behaviour as v1712 you need to adjust these settings correspondingly. Expressed as a conversion table:
featureAngle v1712 | featureAngle v1806 | mergePatchFaces | layerTermination | slipFeature |
0 | 0 | 0 | 0 | 0 |
30 | 58.4 | 30 | 15 | 15 |
45 | 38.3 | 45 | 22.5 | 22.5 |
60 | 180 | 60 | 30 | 30 |
75 | 180 | 75 | 37.5 | 37.5 |
90 | 180 | 90 | 45 | 45 |
120 | 180 | 120 | 60 | 60 |
130 | 180 | 130 | 65 | 65 |