Density field visualization of a micro-explosion using background-oriented schlieren

The determination of flow field properties of large-scale explosions which is necessary for better understanding\ud and flow modeling is rather challenging and difficult. Recent studies show that micro-explosions can be an acceptable substitute. However, quantitative determination of the flow field is still a challenge given the extremely short duration and spatio-temporal evolution of the flow. Determination of shock wave propagation properties from a blast using available flow diagnostic techniques is difficult. The complex nature of the chemical reaction process and spatial and temporally varying flow field imposes serious limitations on applied diagnostics. Most of the earlier works are qualitative in nature (Dewey 2001; Kleine et al. 2003; Klingenberg 1977) where the blast wave properties are derived through Rankine–Hugoniot relations. Sommersel et al. (2008) and Mizukaki et al. (2011) have used the Natural Background Oriented Schlieren technique on large and laboratory scale blasts respectively. They used the BOS technique to get the time-radius relationship of the blast wave; however no direct quantitative density field could be obtained. In this study, density field of a spatial-temporally evolving blast wave generated from a small microexplosion (Obed et al. 2012) is documented using Background Oriented Schlieren (BOS). A preliminary attempt at application of BOS to a micro-explosion was carried out by Suriyanarayanan et al. (2011). In the present study the three dimensional density field was reconstructed using the filtered back projection technique at several instants of time in order to capture the evolution of the density field of the blast wave