Experimental study of electrically charged surface waves

The article deals with the propagation of surface waves in a tank filled with a dielectric liquid. The waves are created by a vibrator, the frequency and amplitude of which are controlled. Two parallel metallic electrodes are placed in the tank and an adjustable potential difference is applied between them. The immerged electrode injects electric charges into the liquid and the top-electrode attracts them. They remain on the liquid-gas interface which therefore becomes electrically charged. A high velocity camera records the shape of the waves and an associated image analysis system extracts from them all the information needed (frequency, amplitude, wavelength) to investigate the influence of the electric charges on the propagation of the waves on the liquid/gas interface as well as the influence of the electrical conductivity of the liquid on the wavelengths. For this purpose we made measurements with different diesel oil electrical conductivities, for various frequencies and amplitudes of waves at different applied voltages.