The effect of an injection of specific momentum at the bottom boundary of an axisymmetric, quasisteady maintained vortex is studied by extending the earlier investigation of . Non-zero vertical velocities at the top of the surface layer representing the lower extremity of a vortex are prescribed. Positive values of the superimposed vertical velocity signified pumping; negative, sucking. The two second-order ordinary differential equations governing the tangential and radial velocities of the vortex are solved by employing Newton's iterative method.
The result, viz., that pumping produces a deeper inflow layer and destabilizes the motion while suction depresses the inflow layer and produces stability confirmed an earlier finding of certain fluid dyhamicists. Modifications of the boundary-layer structure produced by spatially varying the angular momentum distribution of a vortex are analogous to those caused by the imposition of the Taylor boundary condition at the lower extremity of the vortex. They are also similar to those rendered by varying pumping or suction. The latter result is believed to be new while the former simply agrees with an earlier theoretical deduction.