Description: We propose the development of a high fidelity computational approach for unsteady calculations of strongly separated non-equilibrium high-enthalpy hypersonic flows. The goal is to integrate the now proven partially-averaged Navier-Stokes (PANS) method for unsteady flow simulations with the most advanced closure models for compressibility, high-enthalpy (flow - thermodynamics coupling) and non-equilibrium (flow - chemistry coupling) effects. The PANS model has been established as a reliable model for computing separation in low and high speed regimes in two recently conclude NASA NRA projects -- 1. RANS and PANS modeling of hypersonic turbulent mixing environment; 2. Modeling of strongly separated flows with the PANS bridging method. The current proposal is to incorporate further hypersonic effect closures into PANS. Physics-based closure models for flow-thermochemistry interactions have been under development in Girimaji's group at Texas A&M under AFOSR MURI funding -- Transition and Turbulence modeling in non-thermochemical-equilibrium hypersonic flows. Important closure model building blocks for hypersonic processes are now available from the above fundamental research efforts. The combination of PANS and these advanced high-speed models will lead to a unique capability for computing hypersonic flow separation with ablation, chemistry and compressibility effects. For Phase I, we propose a logical sequence of verification-validation computations to demonstrate the potential of the various individual closures in separated high-speed high-enthalpy flows. While in-house codes are available for the proposed development, we will also consider using any of the NASA codes: USM3D, OVERFLOW, VULCAN or any of the other codes suggested by the grantor. Subsequent work (Phase II) will focus on the assembly of the individual components and development of an unique high-fidelity computational capability for hypersonic vehicle design, testing and development.

Benefits: The approach developed here is of great interest in investigations of explosions (DoD), high-speed projectiles and missiles (Air Force, Army), shock and blast waves. An important component of the approach PANS is already available in the commercial code AVL FIRE version 8.31. It is being used by designers for internal combustion engine flows.

The proposed method will lead to a state-of-the-art computational design tool for hypersonic flows with high-enthalpy, ablation and chemistry effects for internal and external flows. Aspects of the method have already been implemented in some NASA codes USM3D and PAB3D. The new capabilities can also be easily incorporated into other codes such as VULCAN, WING, OVERFLOW etc.