44 th AIAA Aerospace Sciences Meeting and Exhibit, 9-12, January 2006, Reno, Nevada American Institute of Aeronautics and Astronautics Paper 2006-0191 1 of 11 MODELING OF NEAR-FIELD BLAST WAVE EVOLUTION Joseph D. Baum, Eric L. Mestreau, Hong Luo Center for Applied Computational Sciences, ACBU SAIC, 1710 SAIC Drive, MS 2-6-9, McLean, VA 22102, USA Rainald Löhner CSI, George Mason University, Fairfax, VA 22030, USA Daniele Pelessone Engineering and Software System Solutions, Solana Beach, CA, 92075, USA Michael E. Giltrud TDSH, Defense Threat Reduction Agency, Alexandria, VA 22060, USA and James K. Gran Poulter Laboratory, SRI International, Menlo Park, CA, 94025, USA This paper describes applications of a coupled Computational Fluid Dynamics (CFD) and Computational Structural Dynamics (CSD) methodology to the simulation of blast waves generated by bare explosive charges in a test facility with rigid and deformable walls. The coupled algorithm combines FEFLO98 (CFD) and MARS3D (CSD) via an embedded approach, where the CSD objects float through the CFD domain. This combination enables an easier and more accurate prediction of structural deformation, cracking and failure under blast loading. Several experiments were conducted to characterize blast load and structural response as a function of charge size, weapon ignition point (nose or tail) and orientation (horizontal or vertical). The numerical simulations helped in understanding the experimental results, some of which were not intuitively understood. Very good agreement between the experimental results and the numerical predictions were demonstrated for pressure data, blast loading and the corresponding structural response. I. Introduction he objective of this study is to validate and apply the coupled CFD/CSD methodology to the simulation of bare/cased weapons detonation/fragmentation, and blast and fragment interactions with rigid and deformable structures. These applications constitute a very severe test to the numerical methodology as they require modeling of several complex and interacting physical phenomena: a) Detonation wave initiation and propagation; b) CSD modeling of case expansion and fragmentation; c) Blast wave diffraction through the breaking case, and around the flying fragments; e) Fragments and airblast impact on the structure; and f) The resulting structural deformation. To model the physics involved, elasto-plastic material models with rupture criteria (CSD) are required, coupled with either the Euler or the Reynolds-Averaged Navier-Stokes (CFD). Two approaches can be used to model fluid/structure interaction. The ‘tight coupling’ approach requires solving both CFD and CSD as one coupled set of equations with the drawback of requiring the complete rewrite of both solvers. The second approach, called ‘loose coupling’, decouples the CFD and CSD sets of equations and uses projection methods to transfer interface information between the CFD and CSD domains. By building on pre- Copyright  2006 by authors. Published by The American Institute of Aeronautics and Astronautics with permission T 44th AIAA Aerospace Sciences Meeting and Exhibit 9 - 12 January 2006, Reno, Nevada AIAA 2006-191 Copyright © 2006 by authors. Published by the American Institute of Aeronautics and Astronautics, Inc., with permission.