Chimera Grid Tools (CGT) is a software package for performing computational fluid dynamics (CFD) analysis utilizing the Chimera-overset-grid method. For modeling flows with viscosity about geometrically complex bodies in relative motion, the Chimera-overset-grid method is among the most computationally cost-effective methods for obtaining accurate aerodynamic results. CGT contains a large collection of tools for generating overset grids, preparing inputs for computer programs that solve equations of flow on the grids, and post-processing of flow-solution data. The tools in CGT include grid editing tools, surface-grid generation tools, volume-grid-generation tools, utility scripts, configuration scripts, and tools for post-processing (including generation of animated images of flows and calculating forces and moments exerted on affected bodies). One of the tools, denoted OVERGRID, is a graphical user interface (GUI) that serves to visualize the grids and flow solutions and provides central access to many other tools. The GUI facilitates the generation of grids for a new flow-field configuration. Scripts that follow the grid generation process can then be constructed to mostly automate grid generation for similar configurations. CGT is designed for use in conjunction with a computer-aided-design program that provides the geometry description of the bodies, and a flowsolver program.

This program was written by William M. Chan and Stuart E. Rogers of Ames Research Center, Steven M. Nash of ELORET Corp., Pieter G. Buning of Langley Research Center, and Robert L. Meakin of the U.S. Army Aeroflightdynamics Directorate. For further information, access the Technical Support Package (TSP) free on-line at under the Software category.

Inquiries concerning rights for the commercial use of this invention should be addressed to

the Technology Partnerships Division
Ames Research Center
(650) 604-2954.

Refer to ARC-15399-1.

NASA Tech Briefs Magazine

This article first appeared in the December, 2005 issue of NASA Tech Briefs Magazine.

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