Optical Diagnostics and Analysis for Multiphase Blast

The damage mechanisms induced by multi-phase blast weapons are not well understood. This is due to the complexity of the phenomenologies associated with weapon effects and also the difficulties associated with measuring and quantifying such phenomena under testing conditions. The proposed Phase I effort will develop an optical imaging and image analysis approach to identify and quantify multi-phase explosive blast field quantities. Optical flow visualization techniques including direct imaging, shadowgraphy, and background-oriented schlieren (BOS) will be evaluated for their relative strengths in imaging shock waves, explosively-driven product gases, and fragments of varying sizes. The imaging will be optimized with multiple camera views and multiple imaging resolutions to allow characterization of fragments with sizes varying from micron to millimeter scales. Image analysis software will be developed and adapted from previous applications to track flow features and fragments during the explosion process. The image analysis will include identification of fluid-dynamic fronts, i.e. shock wave and product gas interfaces, as well as fragments of varied sizes. The output of these analyses will include position-time histories, velocity profiles, and estimated impulse quantities throughout the blast field. The proposed work will include two field tests with fragmenting explosive charges.