[ GiDlist ] Computational Box with Shyne
Posted: Mon Dec 11, 2000 3:06 pm
Hello,
To create a box you can do it "manually" by using:
Geometry-Create-Line... or
Geometry-Create-Object-Prism
If it is something that must be repeated every time, as it seems to be your
case, it is better to implement a simple procedure in TCL-TK to make it
automatically. Several 'problemtypes', specially related to CFD, have already
done it to create the control box.
If your are going to perform an analysis on a sail, be very careful in the
sense that it has a thickness close to zero. It can give several meshing
problems to have a volume with a hole that has a 'volume' of zero.
Previus analysis made with GiD on sails use the following approach:
Sail is discretized with a double surface that has as boundary the same set
of lines. It means that the closed boundary of the two surfaces is the same and
the two surfaces have the same geometric representation but are two different
entities. One of them represent the windward and the other represent the
heeward. To do so, there can be used the following options:
Utilities-Copy ( a 0,0,0 translation with option 'duplicate
entities' unset)
Utilities-Collapse-Lines (and select the boundary lines).
Then, the control volume is divided into two volumes by adding additional
surfaces. In this way, the hole of zero thickness is avoided. If there are two
sails, the aproach is the same having two doubled surfaces and 3 control
volumes.
GiD version 6 has implemented and special option that permits to have a
unique control volume around a zero thickness hole (that would be the sail). To
use it, create the hole with the same doubled surfaces aproach than before and
create the volume with a hole. After this, do:
-Geometry-Create-Contact volume (select the 2 double surfaces).
-Meshing-Mesh criteria-No mesh-Volumes (and select the created contact
volume).
Hope it helps,
On Thu, 07 Dec 2000, you wrote:
I would like to know how to create a computational box that has a center of
0 0 0.
What does LPB mean?
I am trying to put a sail into the box and make it a hole?
Brad
--
Centre Internacional de Mètodes Dr. Ramon Ribó
Numèrics en Enginyeria
http://gid.cimne.upc.es/ramsan ramsan at cimne.upc.es
C/ Gran Capitan s/n,
Modulo C1, Campus Norte UPC, tel. +34 93 401 74 03
E-08034 Barcelona, Spain fax. +34 93 401 65 17
To create a box you can do it "manually" by using:
Geometry-Create-Line... or
Geometry-Create-Object-Prism
If it is something that must be repeated every time, as it seems to be your
case, it is better to implement a simple procedure in TCL-TK to make it
automatically. Several 'problemtypes', specially related to CFD, have already
done it to create the control box.
If your are going to perform an analysis on a sail, be very careful in the
sense that it has a thickness close to zero. It can give several meshing
problems to have a volume with a hole that has a 'volume' of zero.
Previus analysis made with GiD on sails use the following approach:
Sail is discretized with a double surface that has as boundary the same set
of lines. It means that the closed boundary of the two surfaces is the same and
the two surfaces have the same geometric representation but are two different
entities. One of them represent the windward and the other represent the
heeward. To do so, there can be used the following options:
Utilities-Copy ( a 0,0,0 translation with option 'duplicate
entities' unset)
Utilities-Collapse-Lines (and select the boundary lines).
Then, the control volume is divided into two volumes by adding additional
surfaces. In this way, the hole of zero thickness is avoided. If there are two
sails, the aproach is the same having two doubled surfaces and 3 control
volumes.
GiD version 6 has implemented and special option that permits to have a
unique control volume around a zero thickness hole (that would be the sail). To
use it, create the hole with the same doubled surfaces aproach than before and
create the volume with a hole. After this, do:
-Geometry-Create-Contact volume (select the 2 double surfaces).
-Meshing-Mesh criteria-No mesh-Volumes (and select the created contact
volume).
Hope it helps,
On Thu, 07 Dec 2000, you wrote:
I would like to know how to create a computational box that has a center of
0 0 0.
What does LPB mean?
I am trying to put a sail into the box and make it a hole?
Brad
--
Centre Internacional de Mètodes Dr. Ramon Ribó
Numèrics en Enginyeria
http://gid.cimne.upc.es/ramsan ramsan at cimne.upc.es
C/ Gran Capitan s/n,
Modulo C1, Campus Norte UPC, tel. +34 93 401 74 03
E-08034 Barcelona, Spain fax. +34 93 401 65 17