Abstract: To investigate the mechanism of water mitigation on air shock wave due to detonation of explosive surrounded by water, several experiments with an air-gap between explosive and water are carried out in a spherical vessel using the spherical charge and water configurations ignited at the center point of the sphere. The water mitigation concept of confined explosion is studied according to the experimental data, such as travel time of shock wave, pressure, impulse and so on. The mechanism of interaction among air-gap, detonation products and water during explosion is also discussed. The results indicate that the lower air shock wave than explosion without water followed with the continual impact of water spray forms the explosion loading from detonating the charge surrounded by water. It is useful of air-gap between charge and water layer to attenuate the reflected overpressure, quasi-state pressure and impulse, which means the air-gap can be applied to enhance the mitigation effect of water on explosion loading.

Key words: ordnance science and technology, water mitigation, shock wave, air-gap, vessel