Verification of 2-D Detonation Shock Dynamics in conjunction with Los Alamos Lagrangian hydrocode

Aida, Toru¹  Walter, John W.¹  Aslam, Tariq D.¹  Short, Mark¹ 

[1] Los Alamos National Laboratory

关键词: Materials Science(36);    Mathematics & Computing(97);    ACCURACY;    BOUNDARY CONDITIONS;    CONVERGENCE;    DETONATORS;    EXPLOSIONS;    FORTRAN;    LAGRANGIAN FUNCTION;    LANL;    MODIFICATIONS;    VERIFICATION;   

DOI  :  10.2172/1048350
RP-ID  :  LA-UR-12-20792
PID  :  OSTI ID: 1048350
Others  :  TRN: US201217%%25

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来源: SciTech Connect

【 摘 要 】

As the latest version of the fast-tube Detonation Shock Dynamics (DSD) solver is linked with the Los Alamos Lagrangian hydrocode, verification problems from a 2006 DSD report (LA-14277 [1]) have been duplicated with some of the verification criteria changed to more quantitative ones. The observed error convergence is as good as or better than reported in [1], quite possibly due to the careful treatment of floating point numbers to ensure that their precision level is maintained throughout the code. This report duplicates the three sample verification problems in LA-14277 [1] using the Los Alamos ASC Lagrangian hydrocode (FLAG), official release of 3.2 Alpha6 with a few modifications. This version of FLAG is linked with the latest fast-tube Detonation Shock Dynamics (DSD) version beta 2 solver released in 2011 as part of the LanlDSD software product [2]. New verification criteria are used for the arcwave problem where two specific locations are chosen for burn arrival time comparison. For this report FLAG's internal driver code prepares the distance function ({Psi}) and material ID fields from its hydro setup, instead of the stand-alone driver that is being utilized by the other LANL hydrocodes currently interfaced to LanlDSD. As it is implemented in version 3.2 Alpha6, the {Psi} and material ID fields and other parameters are passed from FLAG to the DSD solver directly, and the burn table is directly passed back to FLAG as part of the calling arguments. The burn-front arrival time 'exact' solutions, mentioned in the sequel for the rate-stick and 'arc-wave' problems, are computed using a pair of special-purpose Fortran codes provided by Aslam [3]. In each case an ansatz for the form of the solution is made in which the radius from the detonator center point is used as the independent space coordinate. This leads to a simplified, problem-specific, 1D form of the governing equation. This equation is solved using 2nd-order spatial differencing and the forward Euler method on a very fine temporal and geometric mesh. The boundary conditions are handled exactly at the correct location, with second order accuracy. Care has been taken to ensure that this solution is fully converged. Most other technical details are omitted here as they are comprehensively discussed in [1].