The aerothermodynamics of hypersonic flight is extremely complex. In recent years, there has been renewed interest in this field due to its implications on national security and military applications. However, much of the physics that characterizes hypersonic flight is still unknown or poorly characterized, particularly at regimes where strong thermo-chemical non-equilibrium is present. A key question is to understand how adequately reduced-order formulations, used in computational fluid dynamics design codes, can capture the strong coupling between the fluid mechanics of the gas flow, the local gas-phase thermochemical non-equilibrium, and the transport properties of the high-temperature gas.

With this INCITE project, these researchers will be able to conduct large-scale simulations of hypersonic flow fields based on the fundamental interactions of atoms and molecules in the gas. Through the use of massively parallel Direct Molecular Simulations (DMS), these researchers will enable the computation of flows around geometries at length scales at which experiments have been or will be done. Their first objective is to investigate a canonical hypersonic test case, namely the double-cone flow. Unlike similar calculations in the past, the sole input for this team’s calculation will be the quantum mechanical potential energy surface (PES) that describes interactions between nitrogen molecules and atoms.

The simulations will be conducted using a widely researched ab initio PES and its further recent refinement. The team’s second objective of their research is to investigate a high-enthalpy nitrogen flow over a blunt wedge geometry in collaboration with experimentalists at Texas A & M University in order to characterize the refractive index of the gas under non-equilibrium conditions. Finally, the third objective of their research is to simulate air flows solely based on the various PESs that describe the interactions between the various air constituents. Arguably, the computations in the proposed research will produce the highest-fidelity computational fluid dynamics results obtained to date.