Determination of drag of a circular cylinder

the incident vortex has its maximum tangential velocity at the radius of the core. At this instant, the incident vortex not only distorts but also splits into upper and lower vortices. The pair of shed vortices roll up into a strong vortex of circular shape. At t = 1.5, the split incident vortices interact with the flow in the boundary layer and are convected at different local velocities. The shed vortex is convected at a local velocity, which is much slower than that of the lower split incident vortex as shown in the figure. This occurs because the rotation of the shed vortex is opposite to that of the incident vortex. No additional vortex is shed near the leading edge as seen in the figure. This is because the local angle of attack becomes small. The vortex shedding process at t = 0.6 and t =0.9 is shown in detail in Fig. 2 , which clearly indicates that the vortex pair rolls up into a single circular vortex at / =0.9. Comparisions between the experimental results of Ref. 2 and the present computed ones are not included here because of the different structures and strengths of the incident vortices studied in the experiment and the present analysis. Nevertheless, the predicted distortion and splitting of the incident vortex, and vortex shedding near the leading edge have behaviors similar to those observed in the experiment.2 Conclusions Vortex-wedge interaction is investigated using the hybrid, vortex sheet-random vortex method, including viscous effects, and a fast vortex method, involving a large number of vorticity particles. The Schwarz-Christoffel transformation is applied to generate the grid system around the wedge. The shed vortex is formed by the vorticity particles generated all along the surface. Distortion of the incident vortex during the interaction and the appearance of a secondary shed vortex near the leading edge are clearly presented. A pair of vortices are shed and they roll up into a single circular vortex. It is presumed that a variety of shed vortex patterns may prevail depending upon the incident vortex size, strength, and initial position.