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Title: Linear characteristic-nodal transport method for the two-dimensional (x,y)-geometry multigroup discrete ordinates equations over an arbitrary triangle mesh

Technical Report ·
OSTI ID:7046413

A semi-analytic numerical solution to the two-dimensional (x,y)-geometry multigroup discrete ordinates transport equations over a mesh of arbitrarily shaped triangles is derived. The numerical method uses the analytic solution of the discrete ordinates equations with a linear function for the source to generate a linear representation of the angular flux on the boundaries of the triangle. Two cases must be solved for triangular mesh cells; inflow through one face and inflow through two faces of the triangle. The one inflow side problem is solved by the linear characteristic method. The characteristic solution is used to formulate a linear moment representation of the angular flux on the two outflow faces of the triangle. The two inflow sides case is solved by the linear nodal method. The angular flux on the single outflow face is represented by a linear moment expansion. The coefficients of this expansion are obtained from the solution of the zero'th and first spatial moments of the discrete ordinates equation with a linear source representation. The linear flux coefficients are edge-centered and the cell source data are vertex centered. The moments required for the linear source are formed by finite difference expressions of the vertex source data.

Research Organization:
Los Alamos National Lab., NM (USA)
DOE Contract Number:
W-7405-ENG-36
OSTI ID:
7046413
Report Number(s):
LA-10092-T; ON: DE84013874
Resource Relation:
Other Information: Portions are illegible in microfiche products. Original copy available until stock is exhausted. Thesis
Country of Publication:
United States
Language:
English