Mass transfer to the rear of a sphere in Stokes flow

Abstract

Mass transfer to a sphere, including the rear region, in Stokes flow and at large Péclet numbers, is investigated. By the singular-perturbation technique, six distinct regions of different mass-transfer mechanisms are found. One of these regions, the diffusion layer, has already been solved by the boundary-layer method. Another area, the region at the rear of the sphere, is solved here. The local Nusselt number at the rear stagnation point is found to be 1·192. To predict the mass transfer rate everywhere on the sphere, a composite solution can be formed from the boundary-layer solution and the rear-region solution. In heat- and mass-transfer problems, the method used here complements the boundary-layer methods in predicting the heat- or mass-transfer rate at the rear of an axisymmetric object.