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CFD General Notation System
Standard Interface Data Structures

Document Version 3.1.7
CGNS Version 3.1.3

This document contains the Standard Interface Data Structures (SIDS) definitions for the CFD General Notation System (CGNS) project external link; this project was originally a NASA-funded contract under the AST program, but control has now been completely transferred to a public forum known as the CGNS Steering Committee.

The purpose of this document is to scope the information that should be communicated between various CFD application codes; the target is 3-D multizone, compressible Navier-Stokes analysis. Attention in this document is not focussed on I/O routines or formats, but on the precise description of data that should be present in the I/O of a CFD code or in a CFD database.

This document therefore contains a precise definition of information pertinent to a CGNS database. Specifically, the following information is addressed:

This information is encoded into C-like data structures.

This SIDS document is consistent with CGNS Version 3.1. A list of major changes for earlier versions is available.

The PDF form of the CGNS Standard Interface Data Structures was created using pdflatex, and is designed to be printed. The PDF file may be viewed and/or printed using a variety of freely available software packages, including Acrobat Reader external link, GhostScript external link, and xpdf external link. The HTML form is designed for interactive use, and the contents are listed below.

The complete CGNS Standard Interface Data Structures in HTML form is also available for installation on a local system. This is a gzip'ed tar file (224K, 861K gunzip'ed), and may be downloaded by clicking on the link while holding down the shift key, assuming your browser supports this capability. A dialogue box will appear for you to specify the directory and file name. To unpack the contents, do

   gunzip -c sids.tar.gz | tar xvf -
The files will be extracted and stored in the directory sids. Point your browser to the local file sids/index.html to display the CGNS Standard Interface Data Structures home page. Note that this does not include the PDF form of the manual. Note also that some links, to other manuals, etc., may not work.

This version of the "Standard Interface Data Structures" represents a draft revision of the AIAA Recommended Practice R-101A-2005. This document has not undergone a formal approval vote by the standards committee and is therefore not an approved AIAA consensus document. At the time of release of the next major version of the CGNS data structures, this draft document will be voted on by the committee members and, pending approval, become the next iteration of the AIAA Recommended Practice. The current AIAA Recommended Practice (corresponding to SIDS Document Version 2.4.5, CGNS Version 2.4) is available at the AIAA Online Store external link, and as a PDF file (1.01M, 200 pages) at the CGNS Documentation web site.