Given the "Generic Wing/Body" sample model for the desired modeling kernel,
GridEx is executed. The model file may be opened as a "CAPrI" type from the file dialog box which is accessed via the File->Open menu. It may also be simply imported at startup via the -capri command line argument. For example, assuming the Parasolid modeler is to be used:
GridEx Parasolid -capri generic
(Note the model file extension is not required here)
We then turn our attention to the construction of the far-field boundary.
We first create a Box specifying (0,-10,-10)
as the corner reference point and (7,10,10) as the box dimensions.
We've deactivated the display of the rotation axes and
have also activated the display of the
global coordinate axes, the latter of which are rendered in yellow.
Note the spherical cap
of the configuration has its center at the origin
of the global coordinate system.
We now create a Cylinder
which extends through the Box by entering coordinates of (-10,0,0)
for the first axis reference point, and (15,0,0) as coordinates
for he second reference point. The radius is entered
as 5.0 with the resulting cylinder shown above.
It is desired that the
portion of the Cylinder
which falls within the Box serve as the main section
of the far-field boundary downstream of the nose. To isolate
this section, we invoke the Intersect
facility where we select the Cylinder as the target
volume and the Box as the tool volume. The resulting
solid is shown above.
Actually, we could have reversed the
order of the selections and achieved the same result.
Note that
the rendering of the two initial primitives has been suppressed though
they are still accessible from the Structure Tree shown above.
Here Volume_1 corresponds to our imported model, Volume_2
corresponds to the initial Box, Volume_3 the Cylinder,
and Volume_4
their intersection. We will at this point reinstate the display for the original Box
by expanding the Volume_ 2 folder within the Structure Tree and
selecting each of the six Faces bounding this solid as shown above.
These faces are then rendered by selecting Wireframe under
the Style pull-down menu.
Building upon this we then create a Sphere
centered at (0,0,0) with radius of 5.0 with the result shown above.
We now use the Subtract
facility to isolate the upstream portion of the sphere by selecting the
Sphere
as the target volume and the Box as the tool volume.
The resulting volumes consisting of the upstream portion of the Sphere
and the central portion of the Cylinder are shown above.
Now
using the Unite facility, we select the
Sphere as the target volume and the
Cylinder as the
tool volume with the sum now represented as a single volume entity
shown above.
Our next to last step
is to introduce a plane of symmetry at the z=0 plane, and to achieve this
we define a second Box specifying (-10,-10,-10) as the corner
reference point and (10,10,0) as the box dimensions. The
Subtract facility is then used to extract
that portion of the solid model external to the Box; we select
the Sphere/Cylinder as the target volume and the Box as the
tool volume.
We then use the Subtract
operation once more to remove the volume bounded by the configuration
from that bounded by the Sphere/Cylinder volume. The latter is selected
as the target volume and the former selected as the tool
volume. The resulting solid model shown above is ready for
meshing operations.
