Parallel Mesh Adaptation for Unsteady Blast Simulations on Cartesian Meshes

Speaker: Wade Spurlock, Science and Technology Corporation / NASA Ames Research Center
February 9, 2023

Presentation

Abstract

Mesh adaptation is essential for controlling the cost of large-scale, high-resolution simulations. We propose an efficient parallel unsteady adaptation approach that uses multiple sweeps over the time domain. The simulation is divided into a set of temporal “windows”each having a spatial mesh and time step adapted for a fraction of the total solution time. Since each adaptation pass sweeps over the full temporal domain, meshes for all windows can be constructed simultaneously in an embarrassingly parallel fashion, avoiding the typical bottleneck of sequential adaptation that inhibits scalability. This parallel mesh adaptation method is illustrated on a Mach 3 forward-facing step and is then applied to blast propagation simulations in a heavy atmosphere. The accuracy and efficiency of a full-scale 3D asteroid entry with a 50 MT airburst is examined in detail. The simulation runs on 4000 cores and meshes of over 200 million cells, and it requires a large domain of over 150km downrange and crossrange and physical time extending nearly 8 minutes. The flow converges on fine meshes with small Richardson-based error estimates, establishing confidence in the final adaptive solution. A detailed breakdown of wall-time and computational cost for the 3D results shows that all meshing and adaptation accounts for less than 2% of the total simulation time.

Biography

Wade M. Spurlock is a Research Scientist/Engineer for Science & Technology Corp. in the Computational Aerosciences Branch at NASA Ames. His interests are in computational fluid dynamics, aerodynamics, and aircraft design. He earned a B.S. in Aerospace Engineering from Mississippi State University and a M.S. in Aeronautics & Astronautics from Stanford University. Prior to NASA Ames, he worked at Lockheed Martin Space and on the Vahana eVTOL project at A^3 by Airbus.

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