Suppression of the Karman vortex street and reduction in the frontal drag of a circular cylinder with two vortex cells

Numerical analysis of an unsteady-state two-dimensional incompressible flow at a Reynolds number of 40000 around a circular cylinder with two vortex cells is carried out on the basis of the finite-volume solution of the Reynolds equations closed by the Menter’s shear-stress transport model. The vortex cells are fitted with slots that ensure suction into the central channel via a fan located and through outflow of a low-pressure jet. It is shown that the suction in small-size cells intensifies the circulatory flow inside it and leads to the rearrangement of a large-scale structure of the flow around the cylinder accompanied by suppression of the Karman vortex street and a slightly symmetrical stabilization of the wake. The frontal drag of the cylinder decreases almost by three times with an optimal coefficient of the sucked air rate.