Numerical study of underwater explosion shock loading near a rigid dam

Numerical simulations of underwater explosion shock loading near a rigid dam were performed using a multiphase six-equation model of the diffuse interface method. With a more accurate stiffened gas equation of state (SG-EOS), the blast wave propagation was investigated when an explosion bubble was present below the water–air interface. Pressure time–history curves showed that the underwater explosion shock loading near the corner was much higher than those in other cases as a result of the merging of the reflected shockwaves. Parametric studies were conducted by varying the horizontal and vertical distance factors between the explosion bubble center and the dam wall, as well as the effects of different SG-EOS parameters and explosive intensities. The peak overpressure near the dam increased rapidly because of the shockwave reflection off the dam but attenuated quickly over time. A second pressure peak was generated by the collapse of the cavitation. The first shock peak overpressure was less affected by the SG-EOS parameters than the second cavitation collapse pressure. As the explosive intensity increased, the shockwaves underwater became stronger. The first shock peak overpressure was affected more by the increase in explosive intensity than the second cavitation collapse pressure. The proposed solver enhances our understanding of how UNDEXs affect solid structures, improving blast damage estimation accuracy and strengthening defense capabilities. Furthermore, it has promising applications in ocean engineering, offshore energy exploration, and various other fields.