Aerodynamic Lift and Drag Characteristics of Irregularly Shaped Fragments

An innovative aerodynamic database generation methodology is proposed for arbitrary fragment shapes. This will be achieved with automated CFD methods, using the framework of the Unified Flow Solver (UFS). The UFS features an Adaptive Mesh and Algorithm Refinement (AMAR) procedure for seemlessly coupling rarefied and continuum algorithms inside a simulation. The AMAR automatically creates Cartesian computational grids for arbitrary shapes and executes the analysis in an automated process. This simulation system will provide the analyst with a push-button computational tool for generating a deterministic ensemble of steady-state and tumbling body aerodynamic datasets. The deterministic collection of simulation results from this process will be utilized to formulate probabilistic fragment drag and lift cross range models that can be applied in existing debris tracking modules. This method will capture the complex variability of the lift magnitude and direction with sensitivities to shape, inertial and flow irregularities. In Phase I, A moving body capability will be added to UFS for simulating moving fragment flowfields, and the code will be validated and demonstrated for subsonic to hypersonic and continuum to rarefied aerodynamics predictions. In Phase II, the developed tools will be applied for generating datasets for fragment shapes at a range of combinations of Mach, Reynolds, and Knudsen numbers over the entire potential fragment trajectory space suitable for application in MDA debris tracking tools.