Sandia National Laboratories’ (Sandia’s) Advanced Technology Development and Mitigation (ATDM) components vision has enabled apps such as EMPIRE and SPARC to build on foundational capabilities developed and deployed by other teams, providing great leverage and potential for reuse and increased impact.
Electromagnetic pulse (EMP) environments comprise system-generated and source-region-generated EMP conditions. Many EMP environments must be extrapolated from what can be realized with test facilities; thus, validated computational simulation tools are critical for meeting mission requirements. These problems are numerically challenging to simulate and can span vast length and timescales. Therefore, EMPIRE must deliver advanced electromagnetic and plasma physics code capabilities that will be performant on next-generation hardware architectures. To broaden the range of plasma conditions that can be efficiently simulated, EMPIRE includes kinetic (particle) and fluid (continuum) plasma representations.
The team has demonstrated the capabilities in EMPIRE with simulations of increasingly challenging plasma experiments at higher fidelity than was previously possible. This work is advancing toward the formal validation of EMPIRE capability in the regimes of interest to Sandia. EMPIRE results have also been compared with legacy code results for equivalent simulations, which demonstrated the performance and portability advances that have been enabled by the ATDM and Exascale Computing Project (ECP) program.
Engineering and physics applications for hypersonic reentry have multiple national security implications and represent the complex modeling of physical phenomena and engineering responses that significantly drive exascale computing requirements. SPARC will provide a state-of-the-art hypersonic flight simulation capability on next-generation hardware and will include hybrid RANS-LES turbulence models.
The pacing science challenge problem for SPARC is to perform a virtual flight test of a reentry vehicle in its entirety and to predict the structural and thermal response of the vehicle’s components under simulated reentry environments. Performing this analysis includes the simulation of the flow field around the vehicle by using a turbulence model suited for hypersonic, unsteady turbulent fluid dynamics. The thermal loads generated from the computational fluid dynamics simulation will be used to predict the response of the vehicle’s thermal protection system and internal components. The structural loads generated from pressure and shear stress fluctuations predictions by the turbulence models will be used to analyze the vibrational response of the vehicle and its internal components. This predictive capability, which is being validated simultaneously with the code’s development, will provide the ability to assess reentry vehicle response to trajectories in which little flight test data exists.
Sandia’s ATDM components vision has enabled apps such as EMPIRE and SPARC to build on foundational capabilities developed and deployed by other well-coordinated teams, providing great leverage and potential for reuse and increased impact. For example, EMPIRE has used discretization and linear solver technology deployed in Trilinos to make the development process more efficient. EMPIRE and SPARC both incorporate innovative approaches on several fronts, including the effective use of heterogeneous compute nodes via Kokkos, uncertainty quantification through Sacado integration, embedded mesh refinement and geometry, the implementation of state-of-the-art reentry physics and multiscale models, the use of advanced verification and validation methods, and enabling of improved workflows for users.