资源环境科技发展态势分析平台

The influence of strong horizontal electric field (EH) on different stages of deformation and eventual breakup of the large water drops of 6.6, 7.0, and 7.25mm diameter has been observed in a vertical wind tunnel using high-speed photography. Dumbbell, filament, and bag modes of drop breakup are observed when E-H = 0. However, drops elongate in horizontal direction, mostly develop sharp curvature at their ends, eject a fine jet spray of tiny droplets, and ultimately break up into several droplets in E-H = 500 kVm(-1). Extreme elongation up to 29mm is observed for a 7.0mm diameter drop. Results show that the breakup time, i. e., the time from the drop's extreme prolate shape to its breakup in its final oscillation, ranges from 13 to 41 ms when E-H = 0 and 57-105 ms when E-H = 500 kVm(-1). So although the lifetime of the drop since its suspension to breakup is reduced, its elongation and breakup time increase in EH. It suggests that the effect of E-H in final oscillation before breakup overcomes the effect of hydrodynamic and aerodynamic forces in elongating the drop. Also, no breakup of bag type is observed in E-H = 500 kVm(-1). Moreover, the fragments formed after the drop breakup and tiny droplets ejected by their fragments carry electrical charges of polarity determined by the induced charge on the parent drop in E-H. The significance of the results is discussed in modifying the drop growth and the radar echo-precipitation relationships in thunderclouds.