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A numerical study of the problem of laminar infinite flow of viscous incompressible fluid around a rotating circular cylinder at Reynolds number 50 ≤ Re ≤ 500 and dimensionless rotation rate 0 ≤ α ≤ 7 has been carried out. The parametric map of flow regimes has been constructed, where two zones of steady and two zones of periodic solutions are signed out. The dependencies of the drag and lift coefficients on the rotation rate for Re = 200 are studied in detail. Convergence of the numerical solution to the known asymptotic solution at large α is confirmed. KEY WORDS: flow around the rotating cylinder, viscous fluid, vortex shedding, Magnus effect, periodic flows, numerical simulation arXiv:1312.2787v1 [physics.flu-dyn]

This paper deals with experimental investigation and direct numerical simulation of three-dimensional separated laminar and transitional flows behind a semicircular spanwise rib on a bottom wall of a rectangular channel at Reynolds numbers of up to 480. Particular emphasis is given to the formation mechanism of quasiperiodic large-scale vortex clouds in the mixing layer behind the rib. Vortical structures near the channel axis are formed due to pairing of spiral vortices emerging close to the vertical walls when the corner boundary layers impact on the rib. The effect of the Reynolds number and normalized channel size on the spiraling motion, generation, and shedding of large-scale vortex clouds has been estimated.

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