水中铜丝电爆炸激光阴影及流体模拟研究

The underwater electrical wire explosion(UEWE) is an effective way to obtain strong underwater shock wave(SW). In this paper, a double-lens 4f imaging system was used to reduce the phase difference and a series of laser-backlight shadow images of underwater electrical explosion of copper wire were captured. Combined with the waveforms of electrical signals, the evolution of shadow images was described and analyzed. It is found the first distinct pressure wave is produced before the end of melting, which shows a multilayer structure in the shadow image. This pressure wave propagates at a speed close to the sound velocity in still water, and is then chased and submerged by the main SW. During the vaporization stage, the early distribution of water flow leads to a blurred shadow image boundary. The explosive wire and the main SW show good axial uniformity with smooth and neat boundaries. Based on the measured expansion trajectory of explosive wire, the simulated propagation trajectory of SW is highly consistent with the experimental results. Some important physical information, such as the shock wave form and the pressure of the explosive wire, can also be calculated by the model.