Learning Forum

[gishnutr]

Hi All,

  I am a Fluent user. I have never tried CFX.

1.What are the differences in using CFX and Fluent? 

2. Are they used for any specific kind of problems? If yes, why those problems are for CFX/Fluent?

Thank You.

[raul.raghav]

There is always something new to learn .

1. They are both equally good CFD solvers. Preference primarily depends on the physics of the flow and the user's familiarity with the solver. Below are some main differences that come to my mind right away thinking about the two solvers.

• CFX cannot handle a true 2D mesh. It can handle a pseudo-2D mesh which would be a 1 element thickness 3D mesh. While Fluent can handle 2D meshes with no problems.


• Fluent uses a cell-centered approach while CFX uses a vertex-centered approach. The point being is, Fluent is capable of handling polyhedral mesh and cutcell meshes while CFX sticks to just the traditional tetra and hexa mesh topologies.


• CEL (CFX Expression Language) is also used with CFD-Post. So its easier to define algebraic equations and monitor them during your run with CFX. Fluent needs UDFs for customization which can complicate things for beginners. Fluent has post-processing capabilities of its own while CFX needs a dedicated post-processor.


• Mesh Adaption capabilities are weaker in CFX compared to Fluent. In CFX, "Adaptive meshing is available for single domains with no GGI interfaces and limited physics".


• Fluent is continuously worked upon by the engineers at Ansys and there is a significant improvement made with every new release. CFX definitely lacks the focus that Fluent gets from the developers, in my opinion.


• Simulation acceleration with a GPU is possible in Fluent, while it doesn't benefit CFX.

2. Both the solvers can handle most of the flow physics with some limitations for the both. I believe turbomachinery is one field where CFX has been proving its worth. Fluent is preferred for high Mach number flows (supersonic and hypersonic flows). Fluent has a lot more tutorials easily accessible, which makes learning it a tad bit easier. CFX has limited tutorials available making the learning process a bit harder for a beginner.

Hope this helps!