Computations of the steady viscous flow past a fixed spherical gas bubble are reported for Reynolds numbers in the range 0·1 [les ] R [les ] 200. Good agreement with Moore's (1963) asymptotic theory for the drag coefficient is obtained for R [les ] 40 and with the well-known small-R theory for R [les ] ½. The method of series truncation is used to reduce the problem to a nonlinear two-point boundary-value problem, which is then solved by an accurate and efficient finite-difference procedure.

The free shear layer stemming from a discontinuity in angular velocity at either of two parallel disks in almost rigid rotation with fluid between is re-examined. The sole discrepancy between theory and experiment is unaffected by higher-order approximation unless curvature effects are included, when it is reduced.

We consider steady non-axisymmetric source-sink flow of a perfect gas in a rapidly rotating circular cylinder for the case in which the sources and the sinks are distributed on the top and bottom. We apply a linearized analysis to a small perturbation from the state of rigid-body rotation. We show that the radial pressure gradient plays an important role in the determination of the axisymmetric part of the flow field and that the effects of viscosity and thermal conductivity govern the overall configuration of the non-axisymmetric part. We also show that the transport of gas in the main inner flow is axial and that radial transport is confined to the horizontal boundary layers.