Originating as the Aerodynamics Division Software Library of the 1980s and -90s, this software is a collection of more than 100 software applications, many of them for manipulating the grids and flow solutions associated with computational fluid dynamics (CFD). Underlying these applications are about 30 libraries containing more than 1,200 subroutines, functions, or modules, mostly written in Fortran [90] with a small collection of C translations. Wherever possible, the software is generalized with reuse and portability in mind. These tools often operate on files in PLOT3D and/or Tecplot format, which represent de facto standards at many sites within academia, NASA, and industry. Utilities for treating unstructured data are also included along with a collection of programming tools for manipulating character data. Library names such as geomlib, interplib, optlib, and searchlib suggest the scope of numerics covered, while I/O packages such as tecplot_io, triangulation_io, and xyzq_io can ease development of new applications.

Since the year 2000, this collection has grown considerably in support of the NASA Ames Entry Systems and Technology Division. Much of the CFD for atmospheric entry of space vehicles involves a single layer of structured grid blocks that can be taken advantage of in various ways, such as for efficiently perturbing a volume grid when the surface grid has been perturbed and interpolating the flow field accordingly (Radial_Interp), or for performing the line/surface intersection calculations required by certain radiative heat flux calculations (Lines_of_Sight[_2d] and Hemispheres_of_Sight). Grid generation for any likely axisymmetric entry capsule has been fully automated as the Capsule_Grid procedures. Rapid searching of six kinds of grid is well supported by a module of generic Build_Adt and Search_Adt procedures. Frameworks for unconstrained and constrained optimizations — possibly sequences of related optimizations — are also provided (Qnm_Driver3 and Npopt_Driver).

A SourceForge Web site now supports these CFD Utilities: http://sourceforge.net/projects/cfdutilities/ . One-line descriptions are provided online for each library (and within each library for its subroutines) and for each application. Any of the files may be freely downloaded, and guidelines are provided for installing the libraries (first) as they are needed by applications of interest being downloaded individually.

This work was initiated by David Saunders and Robert Kennelly of Sterling Software for Ames Research Center, and continues to be maintained by David Saunders and Todd White of ERC, Inc. at NASA ARC. NASA invites companies to inquire about partnering opportunities. Contact the Ames Technology Partnerships Office at 1-855-627-2249 or This email address is being protected from spambots. You need JavaScript enabled to view it.. Refer to ARC-14467-1A.

NASA Tech Briefs Magazine

This article first appeared in the August, 2015 issue of NASA Tech Briefs Magazine.

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