COLLISION OF UNSTEADY LAMINAR BOUNDARY-LAYERS

The boundary-layer growth near the equator of an impulsively rotated sphere is considered numerically and analytically. The numerical work is highly suggestive of the presence of a singularity at a finite time at which two of the velocity components and the swirl displacement thickness become infinite. Details of an analytic investigation are presented which is consistent with the gross features of the numerical results. Brief consideration is also given to the flow near the equators of impulsively rotated spheroids and it is shown that the relevant boundary-layer equations for this class of bodies can be written in the same form as those for the sphere. © 1979 Sijthoff & Noordhoff International Publishers.