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[ANSYS Meshing] Greenhouse Model Problem

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Old   April 18, 2011, 15:25
Lightbulb Greenhouse Model Problem
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Hello,

I am trying to create a greenhouse model. To simplify, I've created a box, by a simple extrude, I've made a shell out of it and then put in two "windows" on opposite sides of the now cube shell. The thickness of the shell is relatively VERY small compared to overall dimensions. Next, I use the fill function to create a fluid interior using the "by caps" method. Finally, I create an enclosure around the box that should simulate the environment. The enclosure later will serve to simulate wind. I plan to have one box window set up an "interior" and allow the "wind" from the outside to just flow through the box. However, when meshing, the program just cannot mesh the enclosure fluid. It indicates that number of nodes exceeds limits and that this meshing method does not work. I've tried several types of meshing, but to no avail.

Does anybody have an alternative way of approaching this problem besides the building of the geometry and creating enclosure presented above?

Thank you.

Best Regards
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Old   February 2, 2012, 16:16
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Nick Daish
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Quote:
Originally Posted by gameright View Post
Hello,

I am trying to create a greenhouse model. To simplify, I've created a box, by a simple extrude, I've made a shell out of it and then put in two "windows" on opposite sides of the now cube shell. The thickness of the shell is relatively VERY small compared to overall dimensions. Next, I use the fill function to create a fluid interior using the "by caps" method. Finally, I create an enclosure around the box that should simulate the environment. The enclosure later will serve to simulate wind. I plan to have one box window set up an "interior" and allow the "wind" from the outside to just flow through the box. However, when meshing, the program just cannot mesh the enclosure fluid. It indicates that number of nodes exceeds limits and that this meshing method does not work. I've tried several types of meshing, but to no avail.

Does anybody have an alternative way of approaching this problem besides the building of the geometry and creating enclosure presented above?

Thank you.

Best Regards
Hi gameright

I am looking at a similar problem, namely a closed room containing two open windows on opposite sides and wind blowing in through one and out the other, creating a jet and recirculating region inside. I am a beginner with FLUENT, and was wondering whether you could share with me how you meshed your problem. I am having a hard time getting to grips with DesignModeler and the Meshing software (have only looked at Meshing, let alone TGrid, etc).

Thanks!
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Old   February 13, 2012, 13:29
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Alright. I did eventually get it to work using DM and the Ansys meshing tool. The best way to create this is to make a box (the room), turn the box into a shell with zero thickness walls, fill the shell using caps (do not preserve the body), you will end up with one fluid body with imprints of windows on both sides. You will then create the environment around the fluid body (always use frozen material when you extrude, its a lot easier to manage). Use the Boolean operation to subtract the imprinted fluid body from the environment fluid body (makes sure the environment fluid body is set to "fluid" instead of "solid). Finally, (and this is very important), rename the resulting bodies to something other than body and create a part from both of these bodies and then save and transfer to meshing. Your model should not have any solids or wall thicknesses. This should work. In the meshing tool, name all the walls appropriately, including the windows. You will find when you transfer to fluent that the windows SHOULD be set as interior by default, if not, then set them to interior, if you cannot, then then there is something not right in the previous steps. Let me know if this helps and if there is any specific questions you have. Good luck.

Fyi, I'm also a new Fluent user and it took me a couple of like 4 months to figure this out. :P
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Old   January 16, 2013, 00:40
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Hello,

Why do you say that "the windows SHOULD be set as interior by default ..." In your case, the windows are open; right? If they are closed; they can be separated and they can be named as a wall boundary condition in the name selection (ANSYS Meshing).

Quote:
Originally Posted by gameright View Post
Alright. I did eventually get it to work using DM and the Ansys meshing tool. The best way to create this is to make a box (the room), turn the box into a shell with zero thickness walls, fill the shell using caps (do not preserve the body), you will end up with one fluid body with imprints of windows on both sides. You will then create the environment around the fluid body (always use frozen material when you extrude, its a lot easier to manage). Use the Boolean operation to subtract the imprinted fluid body from the environment fluid body (makes sure the environment fluid body is set to "fluid" instead of "solid). Finally, (and this is very important), rename the resulting bodies to something other than body and create a part from both of these bodies and then save and transfer to meshing. Your model should not have any solids or wall thicknesses. This should work. In the meshing tool, name all the walls appropriately, including the windows. You will find when you transfer to fluent that the windows SHOULD be set as interior by default, if not, then set them to interior, if you cannot, then then there is something not right in the previous steps. Let me know if this helps and if there is any specific questions you have. Good luck.

Fyi, I'm also a new Fluent user and it took me a couple of like 4 months to figure this out. :P
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Old   January 16, 2013, 01:21
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Hello there,

I posted this a while back when I was less experienced. I have moved on to other things but I still do remember what I was trying to say. What I meant is that the option to set the face as interior will be present, in addition to the option to set the face as a wall (for the case when the window is closed).

I have discovered easier ways to imprint window faces onto the solid surface without the need to create shells. The important part in all of this is to rename the faces to unique names other than the default name, "body," and to create one part that contains all the bodies that will be interacting. Otherwise, you will form a non-conforming mesh that will require an interface in fluent to connect. To avoid that complexity, just combine all the bodies into a "part" in DesignModeler. It is the equivalent of combining faces so that two bodies share one face.

I hope this makes things clearer. Good luck.
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Old   January 16, 2013, 03:23
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Of course. That's clear. Thanks.
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