Advanced Reentry Vehicle and Wake Models

At hypersonic flow conditions, the flow field around reentry vehicles is ionized, resulting in electro-optical emissions, detectable radar cross-sections, and attenuation of signals transmitted through the plasma. Ablative heat shields may further increase the levels of electrons in the plasma around the hardbody and in the wake. We propose to extend an existing high-fidelity computational fluid dynamics code to provide accurate flow field simulation data and to couple with existing signature prediction tools. This code, US3D, is a highly scalable implicit unstructured grid method designed for hypersonic flow simulations. It has been used successfully on a wide variety of reentry vehicles, and has a general thermo-chemical nonequilibrium kinetics model that is extensible to the modeling of complex reentry plasma flow fields. Key elements of the proposed work include the implementation of relevant chemical kinetics data for high-temperature air and ablation products, the development of an automated grid generation and smoothing tool for hypersonic reentry configurations, and the development of modules to provide properly formatted data for the existing MDA and DoD signature prediction tools. The resulting tool will provide MDA with a robust, efficient and extensible modeling and simulation capability for reentry vehicle radar cross-sections and optical signatures.