Experimental study on water columns produced by near surface underwater explosion

The morphology and formation mechanism of water columns produced by near surface underwater explosion was studied. By using high-speed camera and synchronous measurement of shock wave pressures, recording the forming process of water column and shock wave pressures, and contrasting those two results, the configuration and formation mechanism of water columns for five scaling depths underwater explosion experiments were analyzed. The 5 scaling depths experiments appeared 3 water column configurations, including spray water column, jet and secondary water dome. The experimental results show that the scaling depths have decisive effects to the water column configuration, and the scaling factor of forming jet has a certain range, and the upper limit is between 0.543 and 0.644. The critical scaling factor to judge the appearance of Bjerknes or Buoyancy jet in Blake Criterion may be a little smaller.