NONLINEAR RELAXATION OSCILLATIONS IN LIQUID HOUR GLASS

We perform a table-top experiment with an hour glass having two nozzle s. The hour glass contains two immiscible liquids, namely water and ke rosene. We observe under certain experimental conditions that the natu re of flow of one liquid through another is intermittent. This intermi ttency depends upon the relative densities and surface tensions of the two liquids. The varied nature of flow is observed with the change of surface tension, by adding a red dye in one liquid (water) while the surface tension of the other liquid (kerosene) is kept constant. To ha ve a better understanding we simulate the above phenomena through an a nalog electronic circuit based on a relaxation oscillator with non-lin ear feedback. Our study reveals some novel and interesting features as sociated with the non-linear fluid how through narrow constrictions un der controlled conditions.