Note on the Self-Sustained Oscillations of a Simple Thermal System

Abstract

Some years ago the author carried out some convection experiments in which a U-shaped narrow tube with water was heated from below and cooled from above. At one occasion, when the ends of the tube were connected with two open water reservoirs (Fig. I), it was observed that the free surface of the reservoirs did raise and lower in a periodic manner, indicating an oscillatory flow through the tube.