Experimental investigations on rising bubbles in stagnant water in vertical capillaries

Abstract

We investigate how the walls of cylindrical capillaries affect the velocity of rising gas bubbles of various diameters. Of course, as the capillary diameter increases, the velocity of the rising bubble will approach the case of free rising. Such systematic experiments on the bubble rise in capillaries, in which the ratio of bubble diameter and capillary diameter is varied from one towards smaller values, can hardly be found in literature. Experiments within the system water/air have been conducted in stagnant water and will be discussed in this paper.