Measurement of the density field around supersonic conical projectiles using quantitative schlieren photography

The density variation around supersonic projectiles is characterized through quantitative high-speed schlieren photography. The projectiles were 10° half-angle sharp cones fired from a 0.50"-caliber (12.7mm-diameter) gun barrel. The projectiles were imaged while traveling at approximately 700 m/s, or approximately Mach 2. A lens-based schlieren system with a high-speed digital camera recorded images which were used to obtain density fields via quantitative schlieren. An inversion algorithm is used to obtain three-dimensional results for density variation from the two-dimensional schlieren projection assuming an axi-symmetric flow. Classical compressible aerodynamics solutions for conical projectiles is presented and used for comparison as a theoretical density profile. Agreement with theory is presented via a line profiles taken from the experimental density reconstruction. The experimentally measured density fields are within a 5% error of the theoretical density variation around the conical projectiles.