An Experimental Determination of the Drag on a Sphere at Low Reynolds Numbers

Abstract

Accurate measurements of the drag on a sphere falling in a viscous medium were carried out for Reynolds numbers between 0.001 and 10.0. When the fractional deviation (D/Ds) − 1 of the actual drag D from the Stokes drag Ds was plotted as a function of the Reynolds number, significant inconsistencies among the results of measurements previously reported in literature and significant differences between these and our own results were revealed. Our experimental results also deviated from most theories available; however, they were consistent with the theory of Proudman and Pearson for vanishingly small Reynolds numbers and at Reynolds numbers between 0.5 and 10 with Carrier's semiempirical modification of Oseen's theory.