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J Roued May 10, 1999 03:35

Unstructured CFD code; Difference ??

What are the main difference between the following unstructured CFD code:

Fluent 5.0 CFX 5.3 STAR-CD v. 3.1

Or it it difficult to compare ?

On the numerical solver fluent has both a uncoupled and coupled solver, CFX is a couled solver. STAR-CD ???

From viewing many www pages. Fluent and STAR-CD are the most used codes.

But is this a question about Fluent is for industris and STAR-CD for universities ??

Thanks in advance.



Raza Mirza May 10, 1999 11:03

Re: Unstructured CFD code; Difference ??
The use of unstrucutred meshes in CFD has been neccisitated because of complexities in real world geometries. Many techniques have appeared in the leading commercial codes such as CFD-ACE+, Fluent, Star-CD and CFX. One of the most commonly advertised capability is using triales (2D) or tetrahedra (3D). But these 'typical' elements fail to produce good mehses for turbulent flows.

Indeed all the unstructured codes are not the same. There are many diferrences besides the solvers. One of the key differetiting factors is the type of elements that is supported. CFD-ACE+ from CFD Research Corporation ( offers many unique features in this regard. I list some of the main discriminators below:

1. CFD-ACE+ supports 'arbitrary' polyhedral cells that gives maximum flexibility in generating and using computational meshes

2. CFD-ACE+ supports fully implicit 'arbitrary interfaces' across computational zones, resulting in tremendous saving in the mesh size

3. CFD-ACE+ provides a fully automatic (CAD-to-grid) Viscous Cartesian Mesh Generation, ideal for visous turbulent flows or otherwise

These discriminators are in addition to the common capabilities offered by other codes, such as

1. Triangular / Tetrahedral Mesh Generation and Support

2. Hybrid (prism-tet) Mesh Generation and Support

Please visit CFD Research Corporation website at to learn more about CFD Research Corporation and CFD-ACE+. You can also email me directly if you have any questions

Judd Kaiser May 13, 1999 13:03

Re: Unstructured CFD code; Difference ??
I haven't personally used the other codes you mention. Based on the experience of our customers, the following are some of the relative strengths of CFX5.

- Ease of use. A consitent, intuitive interface. - Direct import of geometry from all major CAD vendors. - Advanced automatic hybrid mesh generation developed in collaboration with General Electric Aircraft Engines. Inflation from surfaces ensures good resolution of boundary layers. - Coupled multigrid solver developed and tested over the last ten years. Scalability is near linear. - Parallel processing with near linear speed up. - Unix and NT operating systems fully supported for serial or parallel solution.

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