Meshing problem with ansys default mesher

wh88 · September 30, 2011, 02:30

Hello everyone,

Im modeling the flow over a car and i placed my car inside a rectangular domain. I use the Ansys workbench default mesher. Im able to mesh the car in isolation but when its inside the domain, the status bar freezes at 'generating mesh for solid'. I believe solid refers to the domain here. Because of this Im unable to generate a mesh. Please help me out here.

Thanks!

jonny_b · September 30, 2011, 11:06

I think you need to provide more information. Perhaps a screen shot of your domain with and without the rectangle boundary will help, and also a screenshot of your meshed car "in isolation". One thing to ask, when you say "able to mesh the car in isolation" does this mean that you do not have any bounding surfaces outside of the car? If so then I'm assuming you've imported a solid model and not a fluid volume model, if you catch what I'm saying.

wh88 · September 30, 2011, 16:43

Quote:

Originally Posted by jonny_b

I think you need to provide more information. Perhaps a screen shot of your domain with and without the rectangle boundary will help, and also a screenshot of your meshed car "in isolation". One thing to ask, when you say "able to mesh the car in isolation" does this mean that you do not have any bounding surfaces outside of the car? If so then I'm assuming you've imported a solid model and not a fluid volume model, if you catch what I'm saying.

Thank you jonny_b for your reply. I have attached some pictures. I modeled a very simple car with an inlet at the front. The first shows the car in design modeler, without enclosure. The second shows the car inside the enclosure. The third one shows the meshed car. Im able to mesh the car only when I do not include an enclosure. I believe you are right in saying I have no bounding surfaces outside the car in this case. The model is solid.
Im using default settings in the ansys mesher. Currently Im not even able to generate a preview for the enclosure.
Any advice would be much appreciated. Thanks!

jonny_b · October 1, 2011, 20:00

How did you import the geometry into ANSYS Meshing. Did you import a CAD geometry into Design Modeler? If the car is a solid, you need to essentially take the inverse of the car solid. You can do this in Design Modeler very easily using boolean operations performed on the car solid and an arbitrary "bounding solid" that encloses the car. Once you do this you should have an air solid of the car in an and enclosed volume and the mesher should do what you want.

wh88 · October 2, 2011, 16:51

Quote:

Originally Posted by jonny_b

How did you import the geometry into ANSYS Meshing. Did you import a CAD geometry into Design Modeler? If the car is a solid, you need to essentially take the inverse of the car solid. You can do this in Design Modeler very easily using boolean operations performed on the car solid and an arbitrary "bounding solid" that encloses the car. Once you do this you should have an air solid of the car in an and enclosed volume and the mesher should do what you want.

the model was cadded in solidworks and imported into DM. This problem only occurs when i shell the car and add inlets and outlets. After importing the model into DM, i created a box and declared it as an enclosure. Then i go to the mesher and generate the default mesh, but it fails.

jonny_b · October 5, 2011, 16:27

After you perform the enclosure, does only one part exist? Also, I skimmed over the documentation and it states that you need to ensure that the body you are enclosing is a frozen body. Did you check this? Typically when importing a geometry, the default is to "Add Material" you will want to change this to "Add Frozen". This option is located in the properties view pane when you select the import tree node in the outline view pane.

Sorry I didn't respond sooner, got tied up.

September 30, 2011, 02:30	Meshing problem with ansys default mesher	#1
wh88 New Member Join Date: Sep 2011 Posts: 5 Rep Power: 14	Hello everyone, Im modeling the flow over a car and i placed my car inside a rectangular domain. I use the Ansys workbench default mesher. Im able to mesh the car in isolation but when its inside the domain, the status bar freezes at 'generating mesh for solid'. I believe solid refers to the domain here. Because of this Im unable to generate a mesh. Please help me out here. Thanks!

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September 30, 2011, 11:06		#2
jonny_b Member jonathan Join Date: Jun 2009 Posts: 47 Rep Power: 17	I think you need to provide more information. Perhaps a screen shot of your domain with and without the rectangle boundary will help, and also a screenshot of your meshed car "in isolation". One thing to ask, when you say "able to mesh the car in isolation" does this mean that you do not have any bounding surfaces outside of the car? If so then I'm assuming you've imported a solid model and not a fluid volume model, if you catch what I'm saying.

October 1, 2011, 20:00		#4
jonny_b Member jonathan Join Date: Jun 2009 Posts: 47 Rep Power: 17	How did you import the geometry into ANSYS Meshing. Did you import a CAD geometry into Design Modeler? If the car is a solid, you need to essentially take the inverse of the car solid. You can do this in Design Modeler very easily using boolean operations performed on the car solid and an arbitrary "bounding solid" that encloses the car. Once you do this you should have an air solid of the car in an and enclosed volume and the mesher should do what you want.

October 5, 2011, 16:27		#6
jonny_b Member jonathan Join Date: Jun 2009 Posts: 47 Rep Power: 17	After you perform the enclosure, does only one part exist? Also, I skimmed over the documentation and it states that you need to ensure that the body you are enclosing is a frozen body. Did you check this? Typically when importing a geometry, the default is to "Add Material" you will want to change this to "Add Frozen". This option is located in the properties view pane when you select the import tree node in the outline view pane. Sorry I didn't respond sooner, got tied up.