Aerodynamic Drag and Lift Characteristics for Irregularly-Shaped Intercept Fragments

The focus of this proposal is the aftermath of a successful missile intercept, where the resulting fragments fall toward land or sea. This study will develop an approach to quantify shape parameters in a useful way to feed to a designed algorithm set governing lift and drag. The goal will be to enable trajectory analysis based upon lift and drag characteristics. Driving parameters such as the size, mass, velocity, and the material structure will be defined and evaluated as they correlate to a fragment’s lift and drag.Existing approaches have focused on the shape evaluation, formulating a plan to standardize shape parameters to enable a generic set of algorithms. Complex non-linear departure modes, such as tumbling, are difficult to replicate in a wind tunnel environment. For Phase I, computational methods, simulating the aerodynamics, are the most cost effective way of predicting non-linear departures for lift and drag. AVID intends to address this problem in three parts, geometry definition, aerodynamic analysis, and predictive techniques to correlate data. During Phase I, research into each set of prediction methodologies will be conducted with a method selected for further development during Phase II. In preparation for Phase II, AVID will develop a measurement approach for experimentally validating the aerodynamic characteristics of the fragments derived in Phase I. Novel wind tunnel testing techniques and deviations from more standard testing methods will be explored for the best possible test matrix to replicate fragment rotational free fall after impact.