- While a rectilinear mesh can be created with blockMesh, not every mesh
created with blockMesh will satisfy the requirements for being a
rectilinear mesh.
This alternative to blockMesh uses a single block that is aligned
with the xy-z directions and specifications of the control points,
mesh divisions and expansion ratios. For example,
x
{
points ( -13.28 -0.10 6.0 19.19 );
nCells ( 10 12 10 );
ratios ( 0.2 1 5 );
}
y { ... }
z { ... }
With only one block, the boundary patch definition is simple and the
canonical face number is used directly. For example,
inlet
{
type patch;
faces ( 0 );
}
outlet
{
type patch;
faces ( 1 );
}
sides
{
type patch;
faces ( 2 3 );
}
...
- After a mesh is defined, it is trivial to retrieve mesh-related
information such as cell-volume, cell-centres for any i-j-k location
without an actual polyMesh.
STYLE: remove -noFunctionObjects from blockMesh
- no time loop, so function objects cannot be triggered anyhow.
- changed the sectorCoeffs keyword to 'point' from 'axisPt'
for more similarity with other dictionaries.
Continue to accept 'axisPt' for compatibility.
- helps reduce clutter in the topoSetDict files.
Caveats when using this.
The older specification styles using "name" will conflict with the
set name. Eg,
{
name f0
type faceSet;
action add;
source patchToFace;
sourceInfo
{
name inlet;
}
}
would flattened to the following
{
name f0
type faceSet;
action add;
source patchToFace;
name inlet;
}
which overwrites the "name" used for the faceSet.
The solution is to use the updated syntax:
{
name f0
type faceSet;
action add;
source patchToFace;
patch inlet;
}
- old 'DELETE' enum was easily confused with 'REMOVE', which removes
the set, not the elements from the set.
- provide corresponding subtractSet() method
STYLE: HashSet set/unset instead of insert/erase methods in topoSetSource
- simplifies switching to/from bitSet storage
Previously the coordinate system functionality was split between
coordinateSystem and coordinateRotation. The coordinateRotation stored
the rotation tensor and handled all tensor transformations.
The functionality has now been revised and consolidated into the
coordinateSystem classes. The sole purpose of coordinateRotation
is now just to provide a selectable mechanism of how to define the
rotation tensor (eg, axis-angle, euler angles, local axes) for user
input, but after providing the appropriate rotation tensor it has
no further influence on the transformations.
--
The coordinateSystem class now contains an origin and a base rotation
tensor directly and various transformation methods.
- The origin represents the "shift" for a local coordinate system.
- The base rotation tensor represents the "tilt" or orientation
of the local coordinate system in general (eg, for mapping
positions), but may require position-dependent tensors when
transforming vectors and tensors.
For some coordinate systems (currently the cylindrical coordinate system),
the rotation tensor required for rotating a vector or tensor is
position-dependent.
The new coordinateSystem and its derivates (cartesian, cylindrical,
indirect) now provide a uniform() method to define if the rotation
tensor is position dependent/independent.
The coordinateSystem transform and invTransform methods are now
available in two-parameter forms for obtaining position-dependent
rotation tensors. Eg,
... = cs.transform(globalPt, someVector);
In some cases it can be useful to use query uniform() to avoid
storage of redundant values.
if (cs.uniform())
{
vector xx = cs.transform(someVector);
}
else
{
List<vector> xx = cs.transform(manyPoints, someVector);
}
Support transform/invTransform for common data types:
(scalar, vector, sphericalTensor, symmTensor, tensor).
====================
Breaking Changes
====================
- These changes to coordinate systems and rotations may represent
a breaking change for existing user coding.
- Relocating the rotation tensor into coordinateSystem itself means
that the coordinate system 'R()' method now returns the rotation
directly instead of the coordinateRotation. The method name 'R()'
was chosen for consistency with other low-level entities (eg,
quaternion).
The following changes will be needed in coding:
Old: tensor rot = cs.R().R();
New: tensor rot = cs.R();
Old: cs.R().transform(...);
New: cs.transform(...);
Accessing the runTime selectable coordinateRotation
has moved to the rotation() method:
Old: Info<< "Rotation input: " << cs.R() << nl;
New: Info<< "Rotation input: " << cs.rotation() << nl;
- Naming consistency changes may also cause code to break.
Old: transformVector()
New: transformPrincipal()
The old method name transformTensor() now simply becomes transform().
====================
New methods
====================
For operations requiring caching of the coordinate rotations, the
'R()' method can be used with multiple input points:
tensorField rots(cs.R(somePoints));
and later
Foam::transformList(rots, someVectors);
The rotation() method can also be used to change the rotation tensor
via a new coordinateRotation definition (issue #879).
The new methods transformPoint/invTransformPoint provide
transformations with an origin offset using Cartesian for both local
and global points. These can be used to determine the local position
based on the origin/rotation without interpreting it as a r-theta-z
value, for example.
================
Input format
================
- Streamline dictionary input requirements
* The default type is cartesian.
* The default rotation type is the commonly used axes rotation
specification (with e1/e2/3), which is assumed if the 'rotation'
sub-dictionary does not exist.
Example,
Compact specification:
coordinateSystem
{
origin (0 0 0);
e2 (0 1 0);
e3 (0.5 0 0.866025);
}
Full specification (also accepts the longer 'coordinateRotation'
sub-dictionary name):
coordinateSystem
{
type cartesian;
origin (0 0 0);
rotation
{
type axes;
e2 (0 1 0);
e3 (0.5 0 0.866025);
}
}
This simplifies the input for many cases.
- Additional rotation specification 'none' (an identity rotation):
coordinateSystem
{
origin (0 0 0);
rotation { type none; }
}
- Additional rotation specification 'axisAngle', which is similar
to the -rotate-angle option for transforming points (issue #660).
For some cases this can be more intuitive.
For example,
rotation
{
type axisAngle;
axis (0 1 0);
angle 30;
}
vs.
rotation
{
type axes;
e2 (0 1 0);
e3 (0.5 0 0.866025);
}
- shorter names (or older longer names) for the coordinate rotation
specification.
euler EulerRotation
starcd STARCDRotation
axes axesRotation
================
Coding Style
================
- use Foam::coordSystem namespace for categories of coordinate systems
(cartesian, cylindrical, indirect). This reduces potential name
clashes and makes a clearer declaration. Eg,
coordSystem::cartesian csys_;
The older names (eg, cartesianCS, etc) remain available via typedefs.
- added coordinateRotations namespace for better organization and
reduce potential name clashes.
- improve doxygen entries for searchable surfaces.
- support selection of searchable surfaces with shorter names.
Eg,
type box | cylinder | ...;
vs type searchableBox | searchableCylinder | ...;
- functionObjectLibs -> libs
- redirectType -> name
- change deprecated writeCompression flags types to Switch.
- cleanup some trailing ';;' from some dictionaries
