Viscous flow around fluid spheres at intermediate reynolds numbers (II)

Abstract

Abstract Approximate velocity profiles have been predicted for laminar, incompressible flow around solid and fluid spheres for Reynolds numbers up to several thousand. The accuracy of the predicted profiles for solid spheres has been tested in three ways. Drag coefficients, flow‐separation angles and forced‐convection transfer rates calculated from these profiles have been compared with experimental data for solid or rigid spheres. The predicted quantities oscillate about the experimental data as the Reynolds number is increased. Cross‐over points occur at Reynolds numbers of about 20, 100 and 500. The velocity profiles for fluid spheres are of little practical value above Reynolds numbers of several hundred as drop or bubble deformation is significant. Drag coefficient data for solid spheres, liquid drops and gas bubbles showing the effect of dispersed‐phase viscosity on total drag are presented. These data are correlated over the Reynolds number range, 10–100 with a viscosity‐ratio correction factor which was derived theoretically.