Bill,
Thanks for the prompt reply! I think i can understand where you are
coming from on the representation of convex corners. There really is no
way to fully represent these areas with mappings.
I had another question about modifying the grid.C file. I'm in unknown
waters here with remaking Overture. I attempted to enter make in the
overture directory and I get a "no targets specified no makefile
found". I do notice a Makefile.in and a Makefile.save. Should i run
one of those instead? Within them they state that environmental
variables should be defined prior to running though.
Thanks for your help.
Matt
On Sun, Jul 12, 2009 at 11:21 PM, Bill Henshaw <henshaw@xxxxxxxx
<mailto:henshaw@xxxxxxxx>> wrote:
Dear Matt,
At some point the plotting of mixed boundaries was broken. Here is
the fix:
Change Overture/ogshow/grid.C around line 463 from
--- old:
if( parameters.gridOptions(grid) &
GraphicsParameters::plotInteriorBoundary )
ISinteriorBoundaryPoint=0;
else
ISinteriorBoundaryPoint=MappedGrid::ISinteriorBoundaryPoint;
---- new:
if( parameters.gridOptions(grid) &
GraphicsParameters::plotInteriorBoundary )
ISinteriorBoundaryPoint=MappedGrid::ISinteriorBoundaryPoint;
else
ISinteriorBoundaryPoint=0;
-------
After making the change just type 'make' from the main Overture
directory.
As a note, to send *.cmd files just rename them to *_cmd for example.
Convex corners are a contentious issue in my mind. I am
going to rant a bit here but don't take it personally :)
The bottom line is that you are fooling yourself if you
think you are getting an accurate answer near the sharp convex
corner.
I always recommend that the corners be rounded off slightly.
As the mesh is refined the corner can be made sharper if
desired. In this case more and more grid points are added
to resolve the corner where the solution changes rapidly.
You thus will get an accurate answer to a slightly wrong geometry
rather than the wrong answer to the right geometry.
Regards,
Bill
matthew fuller wrote:
Hi,
I have a few questions about some false physical boundaries which
are plotted when using cgins.
To begin, i am mapping a flatback airfoil. Essentially it is an
airfoil with the trailing edge chopped off. This in itself proved
difficult to grid given my limited knowledge of ogen mappings and
ogens seemingly limited ability to map around sharp corners. None
the less i was able to get a very sharp flat trailing edge using
shared sides, mixed boundaries, and no hole cutting. Ogen
indicates
my mappings overlap properly. But, when i read in this grid
file to
cgins the mixed boundary that i specified is still plotted as a
physical boundary. To be clear i can tell by the flow field that
these "false" physical boundaries are not actually recognized by
cgins. They do however look strange and raise questions to their
origin and significance. I have found that by disabling boundary
plotting completely whilst in cgins gets rid them but it also
gets
rid of the airfoil boundary. This make its harder to see
where the
airfoil stops and the flow field begins.
My question is, is there a way to change the representation
of these
mixed boundary boundaries in ogen to prevent them from showing up
when running a simulation? I have attached a screen shot
to show what i mean. Unfortunately
the email client i am using (Gmail) will not let me send .cmd
files
(for fear of malware i suppose) so i can not send my ogen and
cgins
command files.
I would appreciate any insight you can provide on this issue.
Thanks!
Matt
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