LAMINAR BOUNDARY-LAYER ON A CIRCULAR-CYLINDER STARTED IMPULSIVELY FROM REST

A numerical method is presented for calculating the unsteady laminar flow over a circular cylinder started impulsively from rest. The governing boundary-layer equations are solved by using Keller's two-point finite-difference method. In regions where the streamwise velocity develops backflow, the solution scheme is modified by a procedure which accounts for the downstream influence. With this modification calculations were carried further in time and in space than any of the previous solutions. In particular, the calculated local skin-friction coefficients and displacement-thickness values agree with those of Belcher et al. Proudman and Johnson, Collins and Dennis, Bar-Lev and Yang, but do not agree with those of Telionis and Tsahalis. © 1979.