Learning Forum

[Walaa Elhamamy]

Hello everyone,

I generated my mesh in gmsh. I want to select these three openings as inlets for my fluid. I cannot do this in my meshing software. 

Any Ideas on how can I define these in ansys as inlet surfaces?

This photo should show the walls, and these three vents should be my inlets, and the interior should be the fluid which is water. 

[NickFL]

First, the inlet boundary condition is applicable only to faces (2D) only and not cells (3D). From your image above, it looks like 2 of the circles are in the middle of the domain. It would not be necessary to mark these as inlet (would it make physical sense?). Furthermore, if you do not have a faces exactly at that X or Y plane where you are making these, there will be nothing to select. The mesher likely put some cells that go through these planes and it is unlikely that you have a coincident vertical plane at these unless you have taken VERY special care.

That said, what you may want to do it open Fluent Meshing. In the Splash screen choose Meshing not Solving. Here you read in your mesh file. Under Boundary-> Zones -> Separate, a window will open. What you can do is create Local Regions over the desired faces and then Separate the walls. Then using Boundary->Manage you can give these faces a new/more appropriate name.

[Walaa Elhamamy]

Thanks a lot for your reply. Actually, I don't know that the inlet boundary condition is applicable only to faces (2D) only and not cells (3D). 

For some reason, I cannot draw 2D surface mesh in my meshing software (gmsh), because of this I am asking how to add it in ANSYS after inserting the mesh.  When I insert the mesh I can see only (default faces and interior ) in the boundary conditions tab, I don't know where I should define the water. 

I am attaching screenshots, the water should enter from Inlet 1, and then will be distributed in the inner area and enter also from Inlet 2 and Inlet 3. 

you mentioned I should do (Under Boundary-> Zones -> Separate, a window will open. What you can do is create Local Regions over the desired faces and then Separate the walls. Then using Boundary->Manage you can give these faces a new/more appropriate name.) I don't see these options when I open Fluent. 

would you declare it a little for me, according to my case? 

 

 

[NickFL]

I am having difficulty seeing what you are trying to model here. There is are several opening that look like doors in a building. One of these the largest, that you marked 1 above, leads out of the domain. Is the volume to be simulated inside these "walls"? What would be the outlet?

You are in the Fluent solver. I mentioned you need to open it in Fluent Meshing. It looks like you are using Workbench and not the stand-alone. Since you built your geometry & mesh outside of ANSYS I see little reason to use workbench, but if you want to you would open it in the Fluent (with Meshing) component system not Fluent or Fluid Flow (Fluent). In the meshing the pull-down menus will be labeled File, Boundary, Mesh and some others. Here you can deconstruct your mesh as you need using the technique I described above. 

 

[Walaa Elhamamy]

Thanks for your reply, I will try the technique you mentioned, and I hope it will work for me.

I am trying to simulate a water flood, which enters from Inlet 1, and then will go through the building and inlet2 and 3 as well. I want to see the water volume fraction and the velocities according to this flood. All these drawings in the photo are the walls of the building, and inlets 1, 2, and 3 are doors.

Do you have any suggestions for me?

Many thanks to you.

[NickFL]

I am afraid you will have to create your geometry. The volume you create needs to be the inverse of what you have, meaning where the fluid will be. It appears from your mesh, you have created where the solid walls are and meshed these.

Go through the tutorials in ANSYS. This geometry is simple and can quickly be created in DesignModeler or SpaceClaim. Furthermore, it will be easy to generate the named selections in these programs.

[Walaa Elhamamy]

I got it, thanks a lot.