Imposed-Solution Boundaries for Three-Dimensional Hull.
Final rept. Apr 84-Jan 85,
ARMY BALLISTIC RESEARCH LAB ABERDEEN PROVING GROUND MD
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This report describes a new imposed-solution transmissive boundary capability that has been made operational in the BRL version of the airblast HULL hydrodynamics code, which can be used for 3-D blast loading computations on rigid structures. Until this time, 3-D blast loading computations have been done by either mapping a 2-D blast wave into the 3-D grid and assigning simple transmissive boundaries, or by imposing a planar constant value non-decaying wave, or by imposing a decaying wave as defined by the LAMB coding. The boundary values for these input waves could only be imposed at two or three of the boundaries. The new imposed-solution boundaries for 3-D Cartesian coordinates allow the time-dependent definition of flow field conditions to be imposed at all six boundary planes. The flow field conditions for these planes may be obtained from a previously-run 2-D cylindrical HULL computation through the use of a new program HULLUP. This new capability permits better definition of free-field flow conditions at boundaries, and thus extends the time that a given grid will produce results on a target that are uncontaminated by artificial waves from improperly defined boundaries. Listings of the changes to HULL, the HULLUP program, and sample runstreams for HULLUP, KEEL, and HULL are included.
- Numerical Mathematics