Abstract
Experimental data of the drag exerted by the walls of a cylindrical vessel on a sphere falling axially down it through a liquid are given for Reynolds numbers, based on the diameter of the sphere, between 0.05 and 20 000. Existing wall-correction formulae are examined in the light of the new data, the conclusion being that the Francis (1933) and Munroe (1888) equations are the most reliable in the laminar- and turbulent-flow regions respectively. Graphs show the correction to be applied in the intermediate-flow region.