Laminar Boundary Layer on a Rotating Thin Cylinder in an Axial Flow : Effect of Self-induced Pressure Gradient on Separation

For a prescribed external pressure gradient, the laminar boundary layer equations which govern the flow developing on a rotating circular cylinder in an axial flow are solved numerically. It is shown that both self-induced favorable pressure gradient caused by rotation and adverse pressure gradient largely influence the flow fields. Although the solution of the two-dimensional boundary layer equations usually exhibits a singularity at the separation point, in this paper the numerical solutions are obtained to integrate the equations without using special techniques through the separation point and into the region of reverse flow. Alternatively numerical instability and an abrupt change in the slope of stream lines appear downstream beyond the separation point and computation is terminated. It is suggested that the singularity occurs not on the wall but within the boundary layer.