Llnl State Of The Art Codes For Source Calculations

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ISBN 13 :
Total Pages : 8 pages
Book Rating : 4.:/5 (683 download)

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Download or read book LLNL State-of-the-art Codes for Source Calculations written by and published by . This book was released on 1995 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: The explosion-source region is defined as the region surrounding an underground explosion that cannot be described by elastic or anelastic theory. This region extends typically to ranges on the order of 1 km/kt. For the simulation or analysis of seismic signals, what is required is the time resolved motion and stress state at the inelastic boundary. Various analytic approximations have been made for these boundary conditions, but since they rely on near-field empirical data they cannot be expected to reliably extrapolate to different explosion sites. More important, without some knowledge of the initial energy density and the characteristics of the medium immediately surrounding the explosion, these simplified models are unable to distinguish chemical from nuclear explosions, identify cavity decoupling, or account for such phenomena as anomalous dissipation via pore collapse. The purpose here is to document the state-of-the-art codes at LLNL involved in simulating underground (chemical and nuclear) explosions and, in so doing, present an overview of the physics. In what follows, the authors first describe the fundamental equations involved, discuss solution methods, coordinate frames and dimensionality. Then they identify the codes used at LLNL and their limitations. A companion report will describe the factors that most influence the seismic response, i.e., the source properties important for discrimination. That report will emphasize the coupling between the rock properties and the characteristics of the explosion cavity.