CGNS

NACAairfoil

WHAT IS CGNS?
CGNS, which is currently taken to mean "CFD General Notation System," has been developed over the last several years as a joint effort between Boeing, MDC, and NASA. (It originally stood for: "Complex Geometry Navier-Stokes", but this name really does not describe it very well.) It is an effort to STANDARDIZE CFD input and output, including grid, flow solution, connectivity, BC's, and auxiliary information (in much the same way that the PLOT3D-format has become the de-facto standard for grids and flow solutions). CGNS also allows for file-stamping and user-inserted-commenting. It employs ADF (Advanced Data Format), a system which creates unformatted files that are portable across computer platforms.

WHY CGNS?
CGNS will eventually eliminate most of the "translator" programs now necessary when working between machines and between CFD codes. Also, it eventually may allow for the results from one code to be easily restarted using another code. It will hopefully therefore save a lot of time (and money). In particular, it is hoped that future grid-generation packages will generate grids WITH ALL CONNECTIVITY AND BC INFORMATION INCLUDED as part of a CGNS file, saving a lot of time and avoiding potential costly errors in setting up this information after-the-fact.