On the self-excited oscillations of an elastic system containing a bubbling fluid

Abstract

Rocking oscillations of a large cooking pan were observed under certain conditions when the pan was mounted on the torsionally flexible burner of a kitchen electric range. Under typical burner heat conditions, the pan would rock vigorously when its contents were bubbling. No evident source of harmonic forcing was apparent. The cause of these oscillations was traced to the impulsive discharge of steam from bubbles on the surface of the contents of the pan, resulting from the steady flow of heat from the burner during the cooking process. The steam that formed these bubbles rose through the boiling liquid, typically under moderate simmering conditions. In turn, these bubble impulses acted as a random-impulse exciting torque on the mass-elastic system of the pan and burner element, causing the pan to vibrate. This paper presents a theoretical study of the above phenomenon, based on studies made to seek an explanation for the observed oscillations.