Advanced Hybrid Methods for Complex Target Plumes

We propose to develop a new and innovative capability to model complex target plumes by upgrading the SOCRATES-P direct simulation Monte Carlo (DSMC) high altitude plume signature code. This capability will enable SOCRATES-P to simulate 3D plume flowfields in a unified manner, from inside the nozzle to the far field, and include plume-plume, plume-body, angle-of-attack, and other complex target effects. This new capability is based on an advanced and highly accurate CFD/DSMC hybrid numerical method, called low-diffusion DSMC (LD-DSMC), which allows strong coupling between high-density continuum regions and more rarefied regions of the plume flowfield for both steady-state and time-dependent flows. Non-thermal equilibrium (NLTE) chemistry and radiation effects, important for accurate rendering of radiation signatures, will be treated in a consistent and accurate manner throughout the flowfield by an innovative extension of LD-DSMC proposed here. Several computational speed-up procedures are also proposed, which do not compromise model fidelity. Because SOCRATES-P is 3D, parallel, and the DoD standard code for high altitude plume signatures through rendering by its own post-processor and through FLITES, the results of the proposed effort will be immediately useful to the BMDS community.