Numerical Simulation of Bolide Entry with Ground Footprint Prediction
Speaker: Michael J. Aftosmis, NASA Advanced Supercomputing Divison, NASA Ames Research Center
Presentation
Abstract
As they decelerate through the atmosphere, meteors transfer mass, momentum and energy into the surrounding air at tremendous rates. The entry of such bolides produces strong blast waves that can propagate hundreds of kilometers and cause substantial terrestrial damage even when no ground impact occurs. We develop a new technique for meteoroid airburst modeling based upon conservation analysis for the deposition of mass, momentum and energy. These sources are then used to drive simulations of blast propagation using a fully-conservative, finite-volume solver on a multilevel Cartesian mesh. We examine the ability of this method to accurately propagate the blast over hundreds of kilometers of terrain. Initial verification of the method is presented through the canonical problem of a spherical charge. A detailed reconstruction of the 2013 Chelyabinsk meteor provides additional validation. These simulations show very good prediction of the surface overpressure and blast arrival times throughout the ground footprint. Further investigations examine the impact of simplifications to the modeling on both accuracy and computational efficiency using a line-source blast model and a static spherical charge. Both approaches are shown to be useful simplifications and limitations on their use are discussed.
Biography
Michael J. Aftosmis is an Aerospace Engineer in the Computational Aerosciences Branch at the NASA Advanced Supercomputing Division at NASA Ames Research Center in Moffett Field, California. He currently leads the atmospheric propagation and impact effects component of NASA’s Asteroid Threat Assessment Project. Michael has 25 years of experience in the development and application of numerical methods for unstructured and Cartesian grids, computational geometry, mesh generation, adaptation and adjoint methods for error-estimation and shape design. He leads NASA’s Cart3D software development team which supports a community of over 500 users across all NASA mission directorates, the DoD, DOE, academia and industry. His work on the Debris Transport Team for Shuttle Return to Flight was recognized with a NASA Silver Snoopy in 2006 and his contributions have been recognized through numerous NASA Achievement Awards, Research awards of the AIAA, and NASA’s Software of the Year in 2002. Michael has served as an invited lecturer at the von Karman Institute in Belgium, a visiting scientist at the DLR Design Institute for Aerodynamics and his background includes 10 years in the Air Force Research Laboratory. He has served as research advisor/external examiner for Ph.D candidates at MIT, Stanford University, University of Michigan, Georgia Tech and the University of Toronto. Michael holds a S.M. in Aerospace Engineering from MIT, a B.S. from Syracuse University and is an Associate Fellow of the AIAA.