Persistence of shock asymmetries in asymmetric charge detonations*

True spherical explosive charges are extremely difficult to manufacture. This study aims to determine if a more manufacturable shape charge can be used as an approximation of a spherical charge. The hydrocode CTH was used to model the three-dimensional expansion of a PETN spherical charge and one-gram PETN pellets with increasing degrees of asymmetries. The center-initiated spherical charge is used as a baseline for ideal spherical gas expansion and shock wave propagation. The asymmetric charges explore charge geometry and initiation location and the resulting gas expansion and shock wave motions. The control data is compared to the asymmetrical charges to determine the persistence of shock wave asymmetries.   The results here show that a moderately asymmetric charge, which is easier to manufacture, can be a good approximation to a spherical charge after a few diameters of shock wave and product gas expansion.  Asymmetrical charges impact the strength and shape of late-time shock wave features like the secondary shock wave.