Development and evolution of flow over three-dimensional cylinder

By solving the three-dimensional (3D) time-dependent compressible laminar Navier--Stokes equations with a finite-volume method incorporating the third-order-accuracy discretization scheme, the flow structure around a 3D cylinder is investigated and its evolution mechanism is presented in this paper. At high incidence angles, a shed vortex series forms at leeside of the 3D cylinder with its sectional flow pattern very similar to the Karman vortex street developed behind a two-dimensional cylinder. The main, the secondary and the tertiary vortex system compose a hierarchical structure over the 3D cylinder. Each tertiary vortex develops into a new main vortex after the breakaway of its former main vortex, and merges the secondary vortex on its opposite side of the symmetry plane.