Numerical study of vortex shedding suppression and aerodynamic characteristics of three obstacle configurations having two shapes

Two-dimensional incompressible fluid flows around a rectangular shape placed over a larger rectangular shape at low Reynolds numbers have been numerically analyzed in the present work. The vortex shedding is investigated at different arrangements of the two shapes allowing the investigation of three possible configurations. The calculations are carried out for several values of Reynolds numbers ranging from 1 to 200. The effect of the obstacle geometry on the vortex shedding is analyzed for crawling, steady, and unsteady regimes. A special attention is paid to compute the drag and lift forces acting on the rectangular shapes, which allowed determining the best shapes configuration in terms of both drag and lift. The unsteady periodic wake is characterized by the Strouhal number, which varies with the Reynolds number and the arrangements of the two shapes studied. Hence, the values of vortex shedding frequencies are calculated in this work.