Aerodynamic Lift and Drag Characteristics of Irregularly Shaped Fragments

An innovative aerodynamic database generation methodology is proposed for arbitrary missile fragment shapes. This will be achieved with automated CFD methods, using the framework of the Unified Flow Solver (UFS). UFS automatically creates and adapts Cartesian computational grids for arbitrary shapes and executes the analysis in an automated process, seamlessly coupling rarefied and continuum algorithms inside a single simulation system. This simulation system will provide the analyst with a push-button computational tool for generating a deterministic ensemble of steady and tumbling body aerodynamic datasets for fragments of interest. The deterministic collection of simulation results from this process will be utilized to formulate probabilistic fragment drag and lift models that can be applied in existing debris tracking modules. In Phase I, UFS was validated and demonstrated for subsonic to hypersonic and continuum to rarefied aerodynamics predictions, and a moving body capability was implemented and demonstrated for simulating tumbling fragment aerodynamics. In Phase II, the integration of the full 6-DOF tumbling body capability will be completed. The process of generating aerodynamic datasets for fragment shapes at combinations of Mach, Reynolds, and Knudsen numbers encompassing the fragment trajectory space will be established. Drag and lift data will be delivered in the original deterministic set of data points and in a probabilistic format for fragment shape families suitable for insertion in established MDA debris tracking tools.