Measurement of steady electrohydrodynamic fluid motion induced under surface corona discharge by Schlieren photographs

The Schlieren photographs of electrohydrodynamic (EHD) liquid motion induced under gas-phase needle-plate AC corona discharge are shown in this paper. The phenomenon occurs simultaneously with the corona discharge inception. The Schlieren equipment with a highly detection sensitivity is constructed to understand the mechanical aspects. Although the method of Schlieren photographs is not applicable in quantitatively fluid flow measurement, it has enabled us to observe visually a forming process of the EHD liquid motion. A steady EHD liquid motion within some appropriate experimental conditions as a function of liquid viscosity and applied voltage is successfully observed. Some experimentally obtained results show the transient growth behavior of the sequential EHD liquid motion until steady flow.