Three-Dimensional Multi-block

Advanced Grid Generation System

Multi-block... Grids... 3D! What's this stuff used for?

The 3DMAGGS code is an elliptic volume grid generator, used to generate computational domains for Computational Fluid Dynamics (CFD) analyses of aerodynamic vehicles. It was designed to replace the GRIDGEN3D code of the GRIDGEN system software, reducing excessive use of supercomputer resources and provide adequate flexibility in grid point clustering controls. The 3DMAGGS code has been derived from the 3DGRAPE code written by Dr. Reese L. Sorenson of NASA Ames, but has a whole host of added and enhanced features. These include:

Thomas & Middlecoff Source Terms - including options to use only these controls in the 3D elliptic solver, use these source terms to initially guess the Sorenson orthogonality source-terms, or to use them in conjuction with Sorenson orthogonality (GRIDGEN's hybrid controls).

Optimum Grid Point Movements based on the Ad Hoc Method presented by Dr. Ehrlich. Adapted for fortran, this increases the rate of convergence of the 3DMAGGS solver significantly by forcing the grid points to move as fast as possible without inducing solver divergence.

Variable Cell Heights specification which offers more flexibility in the specification of the poisson solver source term for controlling grid line orthogonality incidence with a surface.

Trans-Finite Volume Grid Initialization utilizing Dr. Bharat Soni's blending coefficients. For multiple block decompositions, this initialization may produce suitable volume grids that do not require elliptic smoothing.

Truncation Error Limiting for low precision (32-bit) machines, preventing the solver from diverging due to inaccuracies in update factors to the poisson solver source terms. This can lead to better resolved volume grids based on initial boundary conditions.

Link to GRIDGEN enabling 3DMAGGS to be used as an alternate volume grid generator and creating a more robust set of tools for volume grid generation.

The code develops volume grids typically based on six defining sides of a computational domain or block. It is up to the user to specify the types of controls the solver is to use or enforce for both grid line and grid point placement inside the volume grid. As explained above, the solver has many different options and capabilities. See Effects of 3DMAGGS Controls or the associated abstract for more detail.

The 3DMAGGS code is available to any citizen of the United States of America, and the requesting organization or individual must reside within the borders of the United States of America. To request a Free copy of the 3DMAGGS code, contact Lori Rowland The 3DMAGGS code is Restricted software according to the Arms Export Control Act (Title 22, U.S.C., Sec 2751, et seq.) and The Export Administration Act of 1979, as amended, Title 50, U.S.C., App. 2401, et seq. Violations of these export laws are subject to severe criminal penalties.

When you send the Usage Agreement form, please notify Stephen J. Alter so the request may be tracked. Please address technical questions to Mr. Alter as well.

NASA Official Responsible for Content -- Stephen J. Alter Last Updated November 6, 2002
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