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MARK December 21, 2000 15:23

hi everyone

i have just started using CFX 5.4 for modeling fluid flow through pipes and constriction such as nozzels and orifices.

i have been using Ansys5.5 before, but now we have to move to CFX.

i have cople of questions, first regarding the meshing processes,i am modeling 2d and 3d pipe flow with an orifice (flow meter), what is the best way to get a regulare mesh, it is ok using free mesh, but how to build the model with regulare mesh in both cases 2d and 3d. secondely is there is a web site or other means where i can find more examples than those in the manuals.

and at last how will i calculate the vorticity through the model (with either mesh), and how to calculate the Strouhal number for the flow over cylinder(2d or 3d).

thank you regards mark

Pat Neuman December 29, 2000 12:34

Re: cfx-meshing,examples
I assume that by regular mesh you are refering to a Hexa or Quad mesh and that by free mesh you are refering to a Tetra or Tri mesh.

It is not possible to generate a Hexa mesh in CFX 5.4 Build. You would need to use either ICEM CFD Hexa or CFX 4 Build. Both of these products can be provided by the AEA office that you contact for technical support.

For highly alligned flow, like flow in pipes, hexa meshes will perform much better than tets. Using inflation on you wall boundaries in CFX 5.4 is a good way to improve the quality of results with tet elements.

Dan Williams January 2, 2001 17:47

Re: cfx-meshing,examples
You won't be able to get vorticity out of the flow solver in CFX-5.4 directly. Probably the only way is to export your results to another package which can do it (eg, Fieldview or Ensight) or do it yourself by using a user export module.

Same with Strouhal number. There is no direct way to get this. You will likely have to do some transient animations and estimate it manually.


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