Behaviors of bubble jets induced by underwater explosion of cylindrical charges under free-field conditions

Underwater explosion experiments were carried out for PETN cylinders in a water tank and elementary data about bubble motions under free-field conditions were obtained by using the high-speed photography technology.Results show that the bubble dynamics of cylindrical charges differs from those of spherical ones,and charge mounting modes affect markedly bubble behaviors.For a horizontally mounted cylindrical charge,asymmetric collapse is achieved due to the asymmetric motion of the bubble interface.As a result,an asymmetric jet is formed and the width of the jet varies with the length-diameter ratio of the charge.On the other hand,for a vertically mounted cylindrical charge,a symmetric jet is generated due to the axial symmetric motion of the bubble interface.In the case of equal-weight charges,the velocity of the jet generated by the vertically mounted cylindrical charge is higher than that generated by the horizontally-mounted one.