Metric-Based Hypersonic Anisotropic Adaptive Mesh Refinement (HAAMR) Using Loci/CHEM and AFLR

Simulating the hypersonic flow of spacecraft vehicle reentry with strongly shocked flows poses a particularly challenging problem, which requires significant manual engineering effort or impractical levels of computational resources to accurately resolve complex flow structures. This work addresses the challenge through a Phase I Small Business Technology Transfer (STTR) effort, leveraging both existing technologies and novel technologies such as adaptive mesh refinement (AMR), which can efficiently reduce numerical error in hypersonic flow simulations by providing finer mesh resolution only where it is needed, based on flow phenomena. The approach focuses on 2D nonreacting laminar flow problems, integrating and enhancing the metric-based anisotropic mesh-refinement methods in the widely used Advancing-Front/Local-Reconnection (AFLR) suite of unstructured mesh-generation tools and combining it with numerical method improvements to the Loci/CHEM solver, to better support highly anisotropic fully unstructured 2D grids. The process of passing metric data and grids between Loci/CHEM and AFLR has been automated to provide a clean AMR workflow. With these enhancements, the newly created HAAMR framework is shown to provide comparable flow and surface heat flux results to the Data Parallel Line Relaxation (DPLR) code on detached shock validation cases when solved on a similar grid size. With an accompanying automation script that provides a straightforward user experience, this framework shows significant promise for further enhancements in the ongoing Phase II STTR effort, to improve 2D results for reacting flow simulations and extend the framework into 3D.