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CGNS logo   

CFD General Notation System

CGNS Version 3.1

CGNS Project Group external link

The specific purpose of the CFD General Notation System (CGNS) project is to provide a standard for recording and recovering computer data associated with the numerical solution of the equations of fluid dynamics. The intent is to facilitate the exchange of Computational Fluid Dynamics (CFD) data between sites, between applications codes, and across computing platforms, and to stabilize the archiving of CFD data.

The CGNS project originated in 1994 as a joint effort between Boeing and NASA, and has since grown to include many other contributing organizations worldwide. In 1999, control of CGNS was completely transferred to a public forum known as the CGNS Steering Committee. This Steering Committee is made up of international representatives from government and private industry.

The CGNS system consists of two parts: (1) a standard format for recording the data, and (2) software that reads, writes, and modifies data in that format. The format is a conceptual entity established by the documentation; the software is a physical product supplied to enable developers to access and produce data recorded in that format. All CGNS software is completely free and open to anyone.

In addition to the CGNS documentation, several conference papers and slide presentations are available, as well as minutes from the CGNS meetings and telecons.

The documentation, papers, etc., are generally available in both PDF and HTML form. The PDF files 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.

A CGNStalk mailing list is available for discussion of the CGNS standard and software. To subscribe, fill out the subscription form at the CGNStalk Information Page. You'll receive an automated welcome message when your subscription is activated. Subscription requests are sent to the list owner for approval, so there may be a short delay. Once your subscription is activated, you may send messages to the CGNStalk mailing list by addressing them to cgnstalk@lists.nasa.gov. An archive of the CGNStalk mailing list is also available, to list subscribers only.

Documentation

The various CGNS documents are listed below, and are consistent with the current CGNS version. The home or title page for each of the documents shows the document version number, and the specific CGNS version that the document applies to. Documentation is also available for

Steering Committee Charter
The charter for the CGNS Steering Committee, the public forum responsible for the development, evolution, support, and promotion of the CGNS (CFD General Notation System) standard external link [PDF]

Overview and Entry-Level Document
An introductory document providing an overall view of the purpose and components of CGNS. The Overview is intended as an entry point into CGNS. [PDF]

A User's Guide to CGNS
A concise introduction to many of the most commonly-used features of CGNS, with coding examples using the Mid-Level Library to write and read simple files containing CGNS databases. The User's Guide is intended as a tutorial: light in content, but heavy in examples, advice, and guidelines. Version 1.0 of the User's Guide was also published as NASA/TM-2001-211236, October 2001. [PDF]

Mid-Level Library
Describes a set of routines making up an Application Programming Interface (API) for storing and retrieving data in a CGNS database. Their purpose is to ease the implementation of CGNS by providing CGNS-compliant I/O without the need for detailed low-level programming using the ADF Core routines. These "mid-level routines" are designed to be inserted directly into applications codes, such as flow solvers and grid generators. [PDF]

Standard Interface Data Structures (SIDS)
Precisely defines the "intellectual content" of CFD-related data, including the organizational structure supporting the data and the conventions adopted to standardize the data exchange process. The SIDS, together with the information in the SIDS-to-ADF or SIDS-to-HDF File Mapping Manual, defines the content and organization of a CGNS database. [PDF]

The current SIDS document represents a draft revision of the AIAA Recommended Practice R-101A-2005. The draft 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, the document will be voted on by the committee members and, pending approval, become the next version of the AIAA Recommended Practice. The current AIAA Recommended Practice (corresponding to CGNS Version 2.4) is available at the AIAA Online Store external link, and as a PDF file (copyright AIAA, made available here by permission) at the CGNS Documentation web site.

SIDS-to-ADF File Mapping Manual
SIDS-to-HDF File Mapping Manual
SIDS-to-Python File Mapping Manual
(not available in HTML format yet)
Specifies the exact manner in which, under CGNS conventions, the CFD data structures (the SIDS) are to be stored in, i.e., mapped onto, the file structure provided by the database manager (ADF, HDF, or Python). The File Mapping Manual, together with the information in the Standard Interface Data Structures (SIDS), defines the content and organization of a CGNS database. [SIDS-to-ADF Manual, PDF, SIDS-to-HDF Manual, PDF, SIDS-to-Python Manual, PDF]

Advanced Data Format (ADF) User's Guide
ADF is the original underlying database manager for CGNS. This document defines the structure of an ADF file, and describes in detail the ADF Core, a library of low-level routines used to store and retrieve data in an ADF file. [PDF]

CGNS Tools and Utilities
A variety of tools and utilities for viewing, editing, and manipulating CGNS and ADF files, including the CGNSview, CGNSplot, and Utilities programs in the CGNStools package. Links are also provided to documentation for alternate bindings to the ADF Core and Mid-Level Library routines.

Conference Papers

"The CGNS System," D. Poirier, S. R. Allmaras, D. R. McCarthy, M. F. Smith, F. Y. Enomoto (AIAA Paper 98-3007). [Available from AIAA external link]

"Advances in the CGNS Database Standard for Aerodynamics and CFD," D. M. A. Poirier, R. H. Bush, R. R. Cosner, C. L. Rumsey, D. R. McCarthy (AIAA Paper 2000-0681). [HTML, PDF]

"CFD General Notation System (CGNS): Status and Future Directions," S. M. Legensky, D. E. Edwards, R. H. Bush, D. M. A. Poirier, C. L. Rumsey, R. R. Cosner, C. E. Towne (AIAA Paper 2002-0752). [HTML, PDF; copyright Intelligent Light, made available here by permission]

"Parallel I/O for the CGNS system," Th. Hauser (AIAA Paper 2004-1088). [Available from AIAA external link]

"Impact of CGNS on CFD Workflow," M. Poinot, C. L. Rumsey, M. Mani (AIAA Paper 2004-2142). [Available from AIAA external link]

"CGNS-Based Data Model for Turbine Blade Optimization," H. Iepan, F. Guibault, M.-G. Vallet, Magnan, R. (AIAA Paper 2005-0334). [Available from AIAA external link]

"Checking CFD interfaces in a multi-disciplinary workflow with an XML/CGNS compiler," M. Poinot, E. Montreuil, E. Henaux (AIAA Paper 2005-1155). [Available from AIAA external link]

"Benchmarking Parallel I/O Performance for Computational Fluid Dynamics Applications," P. D. Pakalapati, T. Hauser (AIAA Paper 2005-1381). [HTML, PDF; copyright Thomas Hauser, made available here by permission]

"Application of CGNS software components for helicopter blade fluid-structure strong coupling," M. Poinot, M. Costes, B. Cantaloube (ERF Paper 31-107).

"Benchmarking the CGNS I/O Performance," Thomas Hauser (AIAA Paper 2008-0479). [HTML, PDF; copyright Thomas Hauser, made available here by permission]

"An Efficient and Flexible Parallel I/O implementation for the CFD General Notation System," Kyle Horne, Nate Benson, Center for High Performance Computing, Utah State University, Thomas Hauser, Academic & Research Computing, Northwestern University [PDF; copyright Thomas Hauser, made available here by permission]

Slides

"CGNS Summary," Douglas McCarthy, Boeing Commercial Airplane Group, Open Meeting, Hampton, VA, May 20-21, 1999. [HTML, PDF]

"The CGNS System," Diane Poirier, ICEM CFD Engineering, 29th AIAA Fluid Dynamics Conference, Albuquerque, New Mexico, June 15-18, 1998. [See AIAA Paper 98-3007, above]

"The CGNS System," Armin Wulf, ICEM CFD Engineering, 37th Aerospace Sciences Meeting & Exhibit, Reno, Nevada, January 13, 1999. [HTML, PDF]

"Advances in the CGNS Database Standard for Aerodynamics and CFD," Diane Poirier, ICEM CFD Engineering, 38th Aerospace Sciences Meeting & Exhibit, Reno, Nevada, January 10-13, 2000. [HTML, PDF]

"CGNS CFD Data Standard," John Steinbrenner, Pointwise, Inc., Panel on Standards for Geometry Modeling and Grid Generation, 8th International Conference on Numerical Grid Generation in Computational Field Simulations, International Society of Grid Generation, Honolulu, Hawaii, June 2-6, 2002. [HTML, PDF]

"CFD General Notation System," Bruce Wedan, ANSYS/ICEM CFD, Presentation at NASA Ames, Jan, 2005. [HTML, PowerPoint (345K, 46 pages)]

"CGNS Tutorial Session," 36th AIAA Fluid Dynamics Conference, San Francisco, California, June 5-8, 2006.

"CGNS Tutorial Session," 48th AIAA Aerospace Sciences Meeting, Orlando, Florida, January 4-7, 2010.

Minutes

Minutes are available for the following CGNS Steering Committee meetings and telecons.

2011
   02 Mar  Telecon  (PDF)     02 Feb  Telecon  (PDF)    
 
2010
   01 Dec  Telecon  (PDF)     20 Oct  Telecon  (PDF)     08 Sep  Telecon  (PDF)    
   10 Jun  Telecon  (HTML, PDF)     29 Apr  Telecon  (HTML, PDF)     18 Mar  Telecon  (HTML, PDF)    
   28 Jan  Telecon  (HTML, PDF)    
 
2009
   01 Dec  Telecon  (HTML, PDF)     02 Sep  Telecon  (HTML, PDF)     07 Jul  Telecon  (HTML, PDF)    
   20 May  Telecon  (HTML, PDF)     1 Apr   Telecon  (HTML, PDF)     7 Jan   Meeting  (HTML, PDF)
 
2008
   5 Nov   Telecon  (HTML, PDF)     10 Sep   Telecon  (HTML, PDF)     2 Jul   Telecon  (HTML, PDF)
   7 May  Telecon  (HTML, PDF)     6 Jan  Meeting  (HTML, PDF)
 
2007
   28 Nov  Telecon  (HTML, PDF)     12 Sep  Telecon  (HTML, PDF)     22 May  Telecon  (HTML, PDF)
   21 Mar  Telecon  (HTML, PDF)     10 Jan  Meeting  (HTML, PDF)
 
2006
   4 Oct  Telecon  (HTML, PDF)     2 Aug  Telecon  (HTML, PDF)     10 May  Telecon  (HTML, PDF)
   22 Mar  Telecon  (HTML, PDF)     11 Jan  Meeting  (HTML, PDF)
 
2005
   4 Oct  Telecon  (HTML, PDF)     2 Aug  Telecon  (HTML, PDF)     25 May  Telecon  (HTML, PDF)
   16 Mar  Telecon  (HTML, PDF)     12 Jan  Meeting  (HTML, PDF)
 
2004
   17 Nov  Telecon  (HTML, PDF)     28 Sep  Telecon  (HTML, PDF)     30 Jun  Meeting  (HTML, PDF)
   25 Mar  Telecon  (HTML, PDF)     7 Jan  Meeting  (HTML, PDF)
 
2003
   20 Nov  Telecon  (HTML, PDF)     18 Sep  Telecon  (HTML, PDF)     24 Jun  Meeting  (HTML, PDF)
   29 May  Telecon  (HTML, PDF)     20 Mar  Telecon  (HTML, PDF)     15 Jan  Meeting  (HTML, PDF)
 
2002
   4 Dec  Telecon  (HTML, PDF)     18 Sep  Telecon  (HTML, PDF)     24 Jun  Meeting  (HTML, PDF)
   15 May  Telecon  (HTML, PDF)     13 Mar  Telecon  (HTML, PDF)     14 Jan  Meeting  (HTML, PDF)
 
2001
   6 Nov  Telecon  (HTML, PDF)     6 Sep  Telecon  (HTML, PDF)     12 Jun  Meeting  (HTML, PDF)
   17 May  Telecon  (HTML, PDF)     15 Mar  Telecon  (HTML, PDF)     9 Jan  Meeting  (HTML, PDF)
 
2000
   7 Dec  Telecon  (HTML, PDF)     25 Oct  Telecon  (HTML, PDF)     24 Aug  Telecon  (HTML, PDF)
   21 Jun  Meeting  (HTML, PDF)     11 May  Telecon  (HTML, PDF)     16 Mar  Telecon  (HTML, PDF)
   10 Jan  Meeting  (HTML, PDF)
 
1999
   9 Dec  Telecon  (HTML, PDF)     14 Oct  Meeting  (HTML, PDF)

CGNS Talk Archives

The following gzipped text files are archives of CGNS Talk emails from the past years. Sometimes, these emails can be useful to search for answers to CGNS-related questions that have been posted in the past.

2008-2009
   Archives  (Gzipped Text File)    
 
2006-2007
   Archives  (Gzipped Text File)    
 
2004-2005
   Archives  (Gzipped Text File)    
 
2000-2003
   Archives  (Gzipped Text File)