Drag reduction on a cylinder with rectangular-notched plate

Although many upstream-placed small parts for the reduction of bluff body drag have been proposed in the literature by previous investigators, none of these investigations employed a three-dimensional part to reduce the drag of the system consisting of a bluff body and an upstream small part. In this work, aerodynamic performances of the systems with various rectangular-notched plates were tested experimentally. Experiments have been carried out in a closed-circuit wind tunnel. In all of the time-averaged drag, measurements, the Reynolds number (Re) based on the cylinder diameter (D) was about 12000. The results for the systems consisting of a circular cylinder and upstream rectangular-notched plates (P01, P02, P03, and P04 cases) are compared with that for the single cylinder (case TS) and system consisting of a cylinder and an upstream plain plate (case P00). Irrespective to the type of the upstream plate, of the systems are lower than that of the TS. At very low dimensionless distance between two body, 0 reduction. For g/D>0.25, the performance of the case P04 is very similar to that of the case P00. However, case P03 found to be the most effective in reducing the to minimum at the lowest g/D possible. At g/D=0.75, the of the P00 system is %37 and %11 lower than those of the TS and P00 system, respectively.