Short Duration, High Altitude, Mixed Continuum/Non-Continuum Flowfield

The problem to be addressed within the present proposal is the accurate modeling of high altitude transient phenomena associated with short duration propulsive and/or detonative events taking into account the mixed continuum/rarefied nature of the flow, chemical kinetics, and two-phase flow while leveraging existing computational fluid dynamic technologies to minimizing development time. Past simulation work in the area of mixed continuum/rarefied flows has produced a mature one-way coupled framework for steady-state applications utilizing the CRAFT CFD Navier-Stokes flow solver for the continuum portion of the flow, the Automatic Efficient Generalized Interface Surface (AEGIS) Toolkit for continuum breakdown determination and interfacing, and a representative Direct Simulation Monte Carlo (DSMC) flow solver for the rarefied flow simulation. Application of this methodology to transient problems was also performed but contained many deficiencies from both a numerical and modeling standpoint. Recently, an unsteady framework has been developed for high-altitude transient flows, which relies on a more tightly coupled and synchronized methodology between the continuum and rarefied flows solvers and addresses the many deficiencies of earlier work. This new technology is now leveraged for the present application and will demonstrate the current capabilities. Simultaneously, improvements regarding two-phase flows and hard-body interaction will also be performed.