Underwater electrical explosion of planar wire arrays and shock wave characteristics: Experimental and simulation analysis

Underwater electrical wire explosion (UEWE) in planar arrays enables strong, spatially controllable shock waves (SWs). This work experimentally investigates the UEWE of a single copper wire and planar multi-wire arrays with nearly identical total mass under an initial stored energy of 1.6 kJ. Discharge current and voltage waveforms are used to determine energy deposition before and after vaporization, while a pressure sensor measures the SW peak pressure, pulse width, impulse, and energy density at a fixed stand-off distance. Splitting a single wire into multiple parallel wires only slightly alters electrical matching but significantly increases energy deposition and strengthens the resulting SWs. Relative to a single wire, a 9-wire array enhances the SW peak pressure and energy density by about 124% and 272%, respectively, while nearly halving the pulse width. For both single-and split-wire configurations, the SW amplitude first rises and then falls with total wire mass, and a smaller mass produces steeper fronts and shorter pulses. Inter-wire spacing has little effect on deposited electrical energy but strongly influences SW convergence, yielding an optimal spacing that maximizes amplitude. A three-dimensional simulation model, extended from a single-wire configuration to planar arrays, reproduces the measured enhancement and shows that primary superposition in the gaps and secondary convergence of reflected compression waves dominate far-field amplification and wavefront uniformity. The combined results provide design guidelines for UEWE-based planar arrays, indicating that increasing wire multiplicity and choosing a spacing of roughly one quarter of the wire length effectively enhance SW amplitude and uniformity.