Topological investigation of unsteady laminar juncture vortex system

Topology of the unsteady laminar juncture flows is studied numerically, to observe the existence of the traditional and new topology and the evolution mechanism. Both traditional topology with 'saddle of separation' and new topology with 'saddle of attachment' as most upstream singular point are observed. The creation of the new primary vortex in horseshoe vortex system in both cases is observed as a fold bifurcation process. This new vortex formation found not influencing the near wall topology adjacent to the most upstream singular point. The free end is found playing a vital role in topological evolution from the traditional type to new type. Controlling the free end effect (sweep) can control the topology, thus either of the two types of topology can be obtained by manipulating the free end effect. The study not only provides the existence of the new topology but also extends the idea of free end influences as a controlling parameter of the topological evolution in juncture flows.