Shock wave attenuation using rigid obstacles with large- and small-scale geometrical features

Abstract

Explosions and their resulting shock waves may pose a large threat to both humans and structures alike. The previous research concludes that a logarithmic spiral configuration is effective in focusing shock waves to a focal point. This research outlines shock tube experiments conducted on two types of solid rectangular obstacles placed in a logarithmic spiral shape. The obstacles have a square cross-sectional area, with one set of obstacles being normal square shapes, but the other set of obstacles have three grooves cut out on every side of the obstacle, thus reducing the cross-section area by 10%. High-speed schlieren photography is used to visualize the shock waves and numerical simulations provide supporting data. A comparison in regards to shock wave attenuation between the two obstacle sets is presented. Results conclude that the three-groove obstacle geometry was successful in attenuating the peak pressure and pressure impulse of a reflected shock wave; however, the results for the transmitted shock wave between the two configurations are again inconclusive.