Numerical study on the deformation of the air-water interface by electrohydrodynamic flow

초록

Electrohydrodynamic (EHD) flow results from the interaction of electric fields with ionized charges, becoming more complex in gas-liquid systems due to interfacial deformation. This study analyzed the interfacial deformation induced by corona discharge in an air-water system using two-phase numerical simulations. A fully coupled model was developed to account for the interactions among charge transport, fluid motion, and temporal interfacial deformation under corona discharge. The model was validated experimentally through particle image velocimetry and discharge current measurements. The effects of applied voltage ranging from 5 to 15) kV and height of water ranging from 4 to 12) mm were analyzed. The results showed that higher voltage increased the EHD flow velocity and interfacial deformation depth. The reduced distance between the discharge electrode and the interface further intensified these effects. The relationship among current, flow velocity, and interfacial deformation could be defined. A distinctive observation of self-sustained and periodic interface deformation under EHD flow conditions was presented with a period of 3 s at 12 mm height and 15 kV applied voltage. A phase lag of 0.4 s was observed between fluctuations in current and flow velocity, while maintaining the periodic oscillation. Current oscillations remained within 3% of the mean value, while flow velocity deviations reached 8.9%, indicating significant temporal fluctuations that should not be neglected. This study offers deeper understanding of the relationship among charge transport, flow structure, and interface deformation in gas-liquid EHD systems with potential applications in areas that require precise control of flow and interfacial behavior. © 2025 Author(s).

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