Impact of Roughness Strip Location on Improving Aerodynamic Characteristics of Circular Cylinder

This present study aims to investigate flow over smooth and rough circular cylinders with a full rough surface and locally applied rough patches at different angular locations. The RANS simulation is conducted using commercial software ANSYS Fluent. The numerical investigation is carried out at a Reynolds number of 25,000, and the associated flow (air) velocity is 37 m/s. It is observed that the rough cylinder is very effective in reducing drag when compared with the smooth cylinder. Further, the roughness strips, extended over 15° circumferential locations, are added separately at different angular orientations of 0, 22.5, 37.5, 52.5, 67.5, and 82.5 degrees over the surface of the cylinder. It can be noted that, with the changes in the position of roughness, there is a significant change in the aerodynamic characteristics. When the surface roughness is implemented over the surface, there is a decrease in the coefficient of drag. Particularly, the roughness strip at 37.5° angular orientation shows a superior effect in reducing the drag.