Advances in the CGNS Database Standard for Aerodynamics and CFD

Reno, NV, January 12, 2000

Diane M. A. Poirier
ICEM CFD Engineering, Berkeley, CA

Robert H. Bush
United Technologies Research Center, East Hartford, CT

Raymond R. Cosner
Boeing Phantom Works, St. Louis, MO

Christopher L. Rumsey
NASA Langley Research Center, Hampton, VA

Douglas R. McCarthy
Boeing Commercial Airplane Group, Seattle, WA


Introduction: Objective

The CFD General Notation System (CGNS) was conceived to:

Introduction: History of the CGNS Project

Introduction: CGNS Elements

Chart illustrating data flow between a user application and CGNS software

Introduction: CGNS Main Features

Introduction: Chart of Original SIDS

Chart illustrating node structure for the original SIDS specification

Extension: Unstructured Topology

Chart illustrating Zone_t node structure for unstructured grid

Extension: Elements Data Structure

Element_t is added under the Zone_t data structure to record unstructured elements data:

Chart illustrating Elements_t node structure

Extension: Geometry-to-Mesh Association

Necessary for:


Layer of indirection:

Chart illustrating geometry-to-mesh association

Extension: Family Data Structure

Family_t is added under the CGNSBase_t data structure to record references to geometry files.

Chart illustrating Family_t node structure

Extension: Grid Motion

Chart illustrating RigidGridMotion_t and ArbitraryGridMotion_t node structures

Extension: Iterative and Time-Accurate Data

IterativeOrTemporalData_t associates with each time step or iteration the appropriate data structures for:

Chart illustrating IterativeOrTemporalData_t node structure

Other Extensions Under Review

New Organization: The CGNS Steering Committee

Migration to an ISO Standard

  1. Preliminary Stage - Planning for possible standardization projects (accomplished 1998-99).
  2. Proposal Stage - Culminates in approval to start a new AP project (completed November 1999).
  3. Preparatory Stage - Develop a Working Draft and a New Work Item (planned completion October 2000).
  4. Committee Stage - Consensus is achieved on a Committee Draft (planned completion ~ April 2001).
  5. Enquiry Stage - Vote on Draft International Standard.
  6. National Stage - Vote on Final Draft International Standard (~2002)
  7. Publication Stage - ISO publishes the International Standard.

CGNS Continues to Gain Acceptance

Number of Registered Users

Bar chart showing growth in number uf users