Development of a discrete ordinates code system for unstructured meshes of tetrahedral cells, with serial and parallel implementations
A numerically stable, accurate, and robust form of the exponential characteristic (EC) method, used to solve the time-independent linearized Boltzmann Transport Equation, is derived using direct affine coordinate transformations on unstructured meshes of tetrahedra. This quadrature, as well as the linear characteristic (LC) spatial quadrature, is implemented in the transport code, called TETRAN. This code solves multi-group neutral particle transport problems with anisotropic scattering and was parallelized using High Performance Fortran and angular domain decomposition. A new, parallel algorithm for updating the scattering source is introduced. The EC source and inflow flux coefficients are efficiently evaluated using Broyden`s rootsolver, started with special approximations developed here. TETRAN showed robustness, stability and accuracy on a variety of challenging test problems. Parallel speed-up was observed as the number of processors was increased using an IBM SP computer system.
- Research Organization:
- Air Force Inst. of Tech., School of Engineering, Wright-Patterson AFB, OH (United States)
- OSTI ID:
- 350392
- Report Number(s):
- AD-A-358704/XAB; AFIT/DS/ENP-98-02; TRN: 91020377
- Resource Relation:
- Other Information: TH: Thesis (Ph.D.); PBD: Nov 1998
- Country of Publication:
- United States
- Language:
- English
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