Interface-controlled electric potential oscillations in salt water/density oscillator

Abstract

Detailed studies have been undertaken to understand the mechanism of development of electric potential oscillations in salt water/density oscillator. For this purpose, four types of systems, viz., (i) non-polar/non-polar liquid systems. (ii) polar-polar liquid systems, (iii) aqueous solution of non-electrolyte water systems and (iv) aqueous solution of electrolyte water systems have been chosen. In case of (i) electric potential oscillations are not observed. On the contrary, for other cases both oscillatory upward and downward flow along with electric potential oscillations are observed. Experimental results show that both oscillatory flow and electric potential oscillations are in phase. Further, for all the systems except (i), electric potential increases during upward flow, while it decreases during downward flow thus confirming the streaming potential hypothesis suggested by Srivastava and coworkers. Density gradient and viscosity essentially control the oscillatory flow. In the case of aqueous glycerol-water system, both oscillatory flow and electric potential oscillations stop when the concentration of glycerol solution and consequently its viscosity is too high showing thereby that the two types of oscillations are interrelated.