Study on Attenuation of Underwater Explosion Shock Waves by Bubble Curtain

The shock wave generated by underwater explosions has a significant destructive impact on the surrounding environment. Therefore, it is crucial to implement bubble curtain protection for blast area safety. This study aims to investigate the influence of the number of bubble curtain layers on attenuating underwater explosion shock waves. An underwater explosion model with free water and varying numbers of bubble curtain layers was established using AUTODYN finite element software. Through experimental validation of the numerical model, a formula for calculating peak overpressure of the shock wave was derived, and the impact of different numbers of bubble curtain layers on shock wave attenuation in water was compared. The results demonstrate that employing a bubble curtain can effectively reduce peak overpressure from an underwater blast shock wave, achieving an attenuation ratio as high as 83%. Furthermore, increasing the number of bubble curtain layers can further enhance this attenuation effect, reaching more than 94% reduction in peak overpressure. Specifically, when comparing two-layered and one-layered bubble curtains at a distance of 12 m from the detonation center behind the bubble curtain, there is a reduction in peak overpressure by 61.94%. Similarly, using a three-layered bubble curtain leads to an additional decrease in peak overpressure at this distance by 11.38% compared to using a two-layered one. However, when utilizing four-layered curtains instead of three-layers ones, there is only a marginal decrease in peak overpressure(6.42%) at this same distance. In conclusion, implementing a bubble curtain significantly weakens shock waves within water bodies during explosive events. Moreover, fewer layers within the bubble curtain result in greater attenuation effects. However, diminishing returns are observed with each subsequent increase in layer count.