Use the CFPOST Post-Processor to get more from the Wind-US CFD Analysis Software

With the pre-processing for the Wind-US CFD analysis software accomplished with GMAN and/or MADCAP (and perhaps one or more of the "minor" utilities ), you are ready to run the solver itself. Then, once you have a solution, you need to be able to examine the results. The NPARC Alliance provides the CFPOST utility for this purpose. There are, of course, several excellent commercial post-processors available; some of them can even directly read the “Common Files” that Wind-US uses. FieldView has long had a built-in file reader for structured grids and solutions. A similar reader for unstructured grids also exists, but isn't part of the official FieldView release yet. If you need it, you can get it from the NPARC Alliance.

Just recently, we also got a prototype Common File reader for Tecplot 360 working. While it is still in a very early stage, it does allow you to read both structured and unstructured grids and solutions. I am not aware of Common File readers for other post-processors, but that doesn't mean they don't exist. If you happen to know of one, please let me know.

CFPOST is no replacement for commercial post-processing software, but it has some unique features that make it handy to keep around if you are using the Wind-US CFD analysis software package.

Post-Processing with CFPOST

CFPOST is used to examine the contents of the solution files created by Wind-US. It can be used to perform many varied functions, such as listing and plotting results, generating reports, and producing files for other plotting packages and post-processors.

While CFPOST does create graphical output, its user interface (unlike those of GMAN and MADCAP ) is almost entirely text-based. You can, evidently, link it into Visual3, if you happen to have a platform that supports it, but I've never done it myself.

CFPOST provides commands for the user to precisely specify the information of interest (i.e. the variable you wish to examine), the domain of interest, and the units of measure in which the results are to be presented. These commands can be scripted in order to save work when repeatedly performing similar analyses.

One nice thing about CFPOST is that it understands the relationships between the various variables stored in the solution files (and the grids). Thus, if your grid dimensions are in inches, but you want heat transfer in SI units, CFPOST can internally take care of the unit conversion. Also, you can read in the same chemistry data used by the solver so that the chemical makeup of the flow can be taken into account when computing things like Mach number, pressure, and temperature.

CFPOST can be used to display data on 2-D cut-planes or “crinkle” cuts of the computational domain. The latter are cross-sections which show the actual mesh cell faces closest to a given cut-plane definition. This can be especially useful for examining solutions on unstructured grids.

Various line plots can be generated with CFPOST, and it can also perform a selection of surface and volume integrations. And, if the function you want to see isn't available, you can define your own with the 'calculate' command.

And if that wasn't enough...

So now you know a bit about examining results from the Wind-US cfd analysis software using CFPOST, and the previous page covered the GMAN and MADCAP utilities, which allow you to get a grid ready for Wind-US to use. There are a lot of special-purpose utilities that come with Wind-US. The next part of this review is a quick run-down of some of these utilities .

If you have specific questions about CFPOST, feel free to ask me and I'll be happy to try to answer them.

Alternatively, you can return to the introduction to this review of the Wind-US CFD analysis software .

If learned all you need about the Wind-US code and related utilities, you can check out the review of another CFD analysis software package or return to the Innovative CFD home page and browse one of the other topics.

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