Imploding and exploding circular EHD solitary waves propagatingonto an insulating dielectric liquid layer

摘要

We present an extensive experimental study on an EHD phenomenondiscovered recently: a wave created and propagating at the surface of aninsulating liquid film deposed on a polymer sheet lying itself on ametallic electrode, when switching off the corona effect produced by apoint facing the layers onto the metallic plate. If now we modify theexperiment by having a pin-hole drilled through the sheet at the center,a second wave simultaneously appears, and this one driving inward. Videorecording and image analysis combine to characterize the phenomenon interms of the relevant parameters. From recordings, the wave velocitieshave been measured: they decline with wave propagations, the decaydecreasing with the charging voltage level. The effects of point-planeseparation and of liquid viscosity are also investigated. In addition,the main features of corona pulsing during both the precharging phaseand the subsequent wave-discharging phase have been examined. A roughanalysis giving an explanation of the basic phenomenon is also presented