Falling Sphere Viscometry. I. Wall and Inertial Corrections to Stokes' Law in Long Tubes

Abstract

The classical expression for determining viscosity from sphere fall velocity is Stokes' law. Stokes' law applies in the absence of wall and inertial effects. In the usual experimental apparatus there are wall effects and there may be inertial effects. The objective of this paper is to establish a correlation of wall and inertial corrections to Stokes' law in the range appropriate for falling sphere viscometry, and to present this correlation in a manner convenient for application. The desired correlation is presented in Table II and Figure 5 of the text. The new correlation should be useful in determining the viscosity of Newtonian fluids and in determining the zero shear rate viscosity of polymer solutions.