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Jervds October 30, 2008 07:23

2D Mesh for CFX

I'm trying to do a 2D simulation with CFX. My problem is to make the mesh,the meshing don't give me the option to do the mesh with CFX-mesh, this happens because I'm with a student version, CFX-mesh doesn't work with 2D mesh or i'm doing something wrong?. With 3D simulations I don't have this problem.


Timon October 30, 2008 09:50

Re: 2D Mesh for CFX
Unfortunately CFX has no 2D capability, you need to make a 1-cell thick mesh and perform a quasi-2D simulation by making the sides of the mesh periodic.

Rogerio Fernandes Brito October 30, 2008 10:00

Re: 2D Mesh for CFX
Use symmetric condition and 1 mm for the thickness.

Rui October 30, 2008 11:20

Re: 2D Mesh for CFX
Why symmetric and nor periodic (or, periodic and not symmetric)? And, why 1mm for thickness?

Glenn Horrocks October 30, 2008 20:10

Re: 2D Mesh for CFX

Rogerio Fernandes Brito October 30, 2008 20:33

CFX can't do any 2D simulation. ONLY 3D.
Can CFX do a 2D simulation?

This is discussed in the CFX documentation, but it has been asked so many times on the CFD-Online Forum it is worth repeating. CFX cannot do a 2D simulation.

Is there any way of doing a 2D simulation in CFX? Yes. From a 2D mesh of the geometry, extrude it one element in the normal direction or USE 1 mm of thickness (or 10 mm, or 20 mm, anyway u want).

For a 2D planar simulation this would be one element in the normal vector direction, for a 2D axisymmetric simulation this would be sweeping a small angle with one element. For the planar mesh the extrusion should be approximately equal to the smallest element edge length in the model, for the axisymmetric mesh the sweep should be a small angle, maximum 5 but smaller if you want high accuracy.

In CFX-Pre you should set the top and bottom faces of the extrusion as symmetry planes. If you want to include swirl in the model use periodic boundaries. The remaining boundaries should be set as walls, inlets, openings and outlets to define the flow.

The CFX documentation discusses 2D simulations and it is recommended you read it before proceeding.

Source [1]:

Jervds October 31, 2008 04:54

Re: CFX can't do any 2D simulation. ONLY 3D.
Thanks a lot!!!

Rogerio Fernandes Brito October 31, 2008 06:17

Re: CFX can't do any 2D simulation. ONLY 3D.
ANSYS Fluent v.6.3.26 does 2D simulations.

Glenn Horrocks November 3, 2008 17:34

Re: CFX can't do any 2D simulation. ONLY 3D.

Just about every other CFD software does true 2D simulations. It is the most glaring shortcoming of CFX when compared to its rivals.

Glenn Horrocks

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