designmodeler and mesh and fluent, lose face boundary

uriah · November 12, 2009, 01:31

I just created a pipe with two faces in two ends, another hole was in the middle, i want to give one face of the two end a pressure, and an outlet pressure in the hole face in the middle and try to find the velocity change with the hole size.
I have creasted the cad in designmodeler, and create the fluid volume by enclosure and created the faces with name selected.
the question is that:
1) how can i avoid meshing in the solid body, just meshing in the volume?
2) after meshing, i export to a file and then read it from fluent software, in the boundary conditions i only find the body, i can not find the faces to make the boundary conditions!
i am using ansys workbench 12.
thanks!

jsm · November 12, 2009, 02:12

Hi,

After creation of geometry, you can use "Named Selection" option for applying Fluent boundary condition surfaces (like inlet, outlet...). By the same way, you can define solid region and fluid volume as separate cell regions that can be identified by Fluent.

If you want to mesh only the flow volume, then before going to ansys meshing, you can suppress the solid region (option is available - RMB click on the particular solid volume) in the design modeller itself.

Named selection and suppressing the solid region can be done in ansys meshing also.

uriah · November 12, 2009, 02:59

dear JSM, thank you very much for your reply!
I have tried what you have mentioned. but i can not update the status of meshing in workbench platform! it always tell me that" the mesh cell requires user input before it can be updated", i have tried in workbench platform with creating cfx.
is it true for fluent, you have to export mesh into a file, then start the fluent, and import the film, you can proceeding the analysis? do i have to export mesh file?
thanks

Quote:

Originally Posted by jsm

Hi,

After creation of geometry, you can use "Named Selection" option for applying Fluent boundary condition surfaces (like inlet, outlet...). By the same way, you can define solid region and fluid volume as separate cell regions that can be identified by Fluent.

If you want to mesh only the flow volume, then before going to ansys meshing, you can suppress the solid region (option is available - RMB click on the particular solid volume) in the design modeller itself.

Named selection and suppressing the solid region can be done in ansys meshing also.

jsm · November 12, 2009, 04:07

Hi,

No. If you select "fluid flow fluent", then it is not necessary to export and import the mesh into the fluent. I think that ansys meshing requires some user input. I am not sure about that. Better way is, clear the mesh & mesh the geometry once again after doing named selection.

uriah · November 12, 2009, 10:00

i have checked again, the named slection seems correct. but i am not sure if i really made the volume by enclosure, it seems that the enlosure can only be made with only one body or solid! how can i make a volume with multiple body by enclosure, how can i check if the volume really made in designmodeler? any other way to make the fluid volume?
thanks!

venkat_bits · October 15, 2010, 07:05

Quote:

Originally Posted by jsm

Hi,

After creation of geometry, you can use "Named Selection" option for applying Fluent boundary condition surfaces (like inlet, outlet...). By the same way, you can define solid region and fluid volume as separate cell regions that can be identified by Fluent.

If you want to mesh only the flow volume, then before going to ansys meshing, you can suppress the solid region (option is available - RMB click on the particular solid volume) in the design modeller itself.

Named selection and suppressing the solid region can be done in ansys meshing also.

hi jsm,
currently im dng flow analysis in 3D in ansys multiphysics ...can u tel me how to select the flow volume in the 3d model and how to suppress the solid model in order to mesh the flow volume...

PSYMN · October 16, 2010, 04:31

Uriah,

Fluent is trying to tell you that the upstream operation (mesh generation) is out of date, so there is no mesh to start the fluent setup with. If you look at the WB schematic you will see that the mesh field doesn't have a checkbox. Just select that field and click "update". The mesh will generate and you will be able to proceed to Fluent.

Venkat_Bits,

In ANSYS meshing you may have noticed that there are 4 little selection filters in the strip above the graphics window. The one is a green box for selecting bodies, the one to the left of that it is a box with only one green face for selecting faces etc. When applying named selections to faces as fluent bocos, you would make sure you were in the mode to select faces. For bodies, just change the mode to the select bodies mode, then select the body, right click and create the Named Selection (such as FLUID or SOLID).

If you want a body to be suppressed (so it is not meshed or exported), just right click on the part in the model tree (under the geometry branch) and choose the suppress option. Or you could do it thru the screen with a right click on a body.

November 12, 2009, 01:31	designmodeler and mesh and fluent, lose face boundary	#1
uriah New Member yang Join Date: Nov 2009 Posts: 3 Rep Power: 16	I just created a pipe with two faces in two ends, another hole was in the middle, i want to give one face of the two end a pressure, and an outlet pressure in the hole face in the middle and try to find the velocity change with the hole size. I have creasted the cad in designmodeler, and create the fluid volume by enclosure and created the faces with name selected. the question is that: 1) how can i avoid meshing in the solid body, just meshing in the volume? 2) after meshing, i export to a file and then read it from fluent software, in the boundary conditions i only find the body, i can not find the faces to make the boundary conditions! i am using ansys workbench 12. thanks!

November 12, 2009, 02:12		#2
jsm Senior Member JSM Join Date: Mar 2009 Location: India Posts: 192 Rep Power: 20	Hi, After creation of geometry, you can use "Named Selection" option for applying Fluent boundary condition surfaces (like inlet, outlet...). By the same way, you can define solid region and fluid volume as separate cell regions that can be identified by Fluent. If you want to mesh only the flow volume, then before going to ansys meshing, you can suppress the solid region (option is available - RMB click on the particular solid volume) in the design modeller itself. Named selection and suppressing the solid region can be done in ansys meshing also. __________________ With regards, JSM

November 12, 2009, 04:07		#4
jsm Senior Member JSM Join Date: Mar 2009 Location: India Posts: 192 Rep Power: 20	Hi, No. If you select "fluid flow fluent", then it is not necessary to export and import the mesh into the fluent. I think that ansys meshing requires some user input. I am not sure about that. Better way is, clear the mesh & mesh the geometry once again after doing named selection. __________________ With regards, JSM

November 12, 2009, 10:00		#5
uriah New Member yang Join Date: Nov 2009 Posts: 3 Rep Power: 16	i have checked again, the named slection seems correct. but i am not sure if i really made the volume by enclosure, it seems that the enlosure can only be made with only one body or solid! how can i make a volume with multiple body by enclosure, how can i check if the volume really made in designmodeler? any other way to make the fluid volume? thanks! Last edited by uriah; November 12, 2009 at 20:46.

October 16, 2010, 04:31		#7
PSYMN Senior Member Simon Pereira Join Date: Mar 2009 Location: Ann Arbor, MI Posts: 2,663 Blog Entries: 1 Rep Power: 47	Uriah, Fluent is trying to tell you that the upstream operation (mesh generation) is out of date, so there is no mesh to start the fluent setup with. If you look at the WB schematic you will see that the mesh field doesn't have a checkbox. Just select that field and click "update". The mesh will generate and you will be able to proceed to Fluent. Venkat_Bits, In ANSYS meshing you may have noticed that there are 4 little selection filters in the strip above the graphics window. The one is a green box for selecting bodies, the one to the left of that it is a box with only one green face for selecting faces etc. When applying named selections to faces as fluent bocos, you would make sure you were in the mode to select faces. For bodies, just change the mode to the select bodies mode, then select the body, right click and create the Named Selection (such as FLUID or SOLID). If you want a body to be suppressed (so it is not meshed or exported), just right click on the part in the model tree (under the geometry branch) and choose the suppress option. Or you could do it thru the screen with a right click on a body.