
Accession Number : ADA302821
Title : Influence of Geometric Approximations on Computational Results in Complex Tunnel Configurations.
Descriptive Note : Final rept.,
Corporate Author : SCUBED ALBUQUERQUE NM
Personal Author(s) : Ekler, Robert G. ; Kennedy, Lynn W. ; Needham, Charles E.
PDF Url : ADA302821
Report Date : SEP 1995
Pagination or Media Count : 57
Abstract : This report describes a series of calculations undertaken to compare the effects of geometric approximations/simplifications commonly made when setting up hydrodynamic code simulations of blast and flow in tunnel systems. The approximations are made to save computer resources by running the calculation in two, rather than three, dimensions. A twodimensional calculation requires less computational time by a factor of one to two orders of magnitude. It also requires less memory to run and less storage space for the computational output. In addition, setup and analysis times are reduced. The questions to be answered by this set of calculations, which included two different twodimensional representations as well as a threedimensional representation, are whether the approximations provide results that are sufficiently dose to those provided by calculating in three dimensions, and if so, which twodimensional approximation is the best. The three calculational representations are set up in the coordinate systems available in SHARC (SCubed Hydrodynamic Advanced Research Code), a stateoftheart, second orderaccurate, multimaterial Eulerian hydrocode. These include a twodimensional cylindrical system, a twodimensional Cartesian (rectangular) system, and a threedimensional Cartesian system. Each representation includes an explosive in a detonation chamber, an input tunnel, an expansion chamber, and an output tunnel connecting to the exterior. For each chamber, crosssectional areas and chamber volumes are the same in each configuration. Yield of the explosive source must also be conserved among the different representations. How this was accomplished is explained in detail in the next section; however, the twodimensional representations are not unique, and some alternatives are discussed in Section 6.
Descriptors : *TUNNELS, *GEOMETRY, *HYDRODYNAMIC CONFIGURATIONS, INPUT, OUTPUT, SIMULATION, SOURCES, VOLUME, COMPUTATIONS, COMPUTERS, TWO DIMENSIONAL, EXPLOSIVES, TIME, CODING, CYLINDRICAL BODIES, APPROXIMATION(MATHEMATICS), COORDINATES, CROSS SECTIONS, HYDRODYNAMIC CODES, RESOURCES, EXPANSION, SPACE(ROOM), STORAGE, BLAST, CHAMBERS, DETONATIONS.
Subject Categories : Fluid Mechanics
Distribution Statement : APPROVED FOR PUBLIC RELEASE