Control of vortex shedding, forces and heat transfer from a square cylinder at incidence by suction and blowing

This numerical investigation aims to study the control of the vortex shedding, heat transfer and the reduction of oscillatory forces from a perforated square cylinder at incidence (α=0−45°) via blowing and suction, Re = 100-200 and Pr = 0.71. At the early stage of investigation, four control cases are studied for Re = 150 and α=45°, where blowing or suction is applied only on the front or rear sides of the cylinder. The advantages of these cases are used to find the optimum conditions, where vortex shedding suppression occurs and a reduction of about 39% in the drag coefficient is provided. For the optimum control case, the effect of Reynolds number (Re = 100-200) is investigated and it is observed that vortex shedding is suppressed and the fluctuations in forces are removed for all Reynolds numbers employed. Also by increasing the Reynolds number from 100 to 200, the drag coefficient decreases about 10%, while the average Nusselt number increases about 85%. In addition, the optimum conditions are also found for different incidence angles (α=0−45°). The maximum and minimum reductions on the drag coefficients occur at angles of 5° and 20°, which are about 95% and 31% at Re = 150, respectively.