Semi-cylindrical shock waves and blade-shaped supersonic jets generated by underwater electrical explosions of wire arrays

We present the results of experimental studies and two-dimension hydrodynamic simulations of underwater electrical explosions of semi-cylindrical wire arrays. In the experiments, a pulse generator delivers a current pulse of ∼250 kA amplitude rising in ∼1 µs to a 5-mm radius semi-cylindrical array of copper or aluminium wires. Experiment and simulation results display the generation of a radially symmetric and converging strong shock wave (SSW) and the generation of a blade-shaped supersonic water jet with a velocity reaching 1.6 km/s. Simulations predict that in the vicinity of the implosion axis, the density, pressure and temperature can reach 1.5 g/cm ³ , 6×10 ⁹ Pa and 500 K, respectively. Additionally, the simulations show that the internal structure of the jet is not uniform, consisting of bubbles and voids that result in significantly smaller density than the normal density of water. Finally, explosions of arrays of different diameter wires result in the generation of converging SSW with satisfactorily uniform azimuthal distribution. This indicates on a resistance positive feedback mechanism that stabilizes the explosion process across wires of different diameters.