Narrow Results

We experimentally investigate the breakup process of a circular oil film with a hole on water surface using PIV and flow visualization. The hole moves to the bound of the oil slick driven by surface tension, and then the slick breaks into smaller drops. Typical flow maps and velocity fields are given. It is shown that a pair of vortices forms at initial stage, the position of the vortices varies as the hole approaches the bound of the slick. Satellite drops arise when breakup occurs and the size of the satellite drops depend on the shape of the slick.

The external strong magnetic field coupling with shaped charge is an effectively method to increase the penetration capability of the shaped charge jet. In this study, a theoretical model was developed to analyze the effect of the external strong magnetic field on breakup time and inhibition of rotation and drift of the shaped charge jet. The discharge current of the circuit system and the magnetic field of the shaped charge jet undergoing were calculated in detail. A series of depth of penetration (DOP) experiments were conducted to analyze the coupling mechanism between the external magnetic field and the shaped charge jet. Theoretical and experimental results indicated that the external strong magnetic field coupling with shaped charge jet can effectively improve the stability of the shaped charge jet, which the magnetic field can delay its breakup time and inhibit its rotation and drift. The ability of penetration of the jet produced by the Ø56 mm shaped charge is increased by 69.13% under the action of the external magnetic field.