Numerical analysis of drag and lift reduction of square cylinder

Flow around an extended triangular solid (thorn) attached to a square cylinder is investigated numerically. The numerical analysis is carried out at low Reynolds number, Re = 100 & 180 for different non-dimensional thorn lengths (l΄ = 0. 2, 0.4 & 0.6), different inclination angles (θ = 5°, 10°, 15° and 20°) and two different thorn positions. It is found that drag and lift reduction can be achieved by attaching the thorn on a square cylinder. It is observed that the fluctuation of the drag force as well as the lift force is reduced and there is a comparatively large variation of drag and lift when the thorn is placed at the front stagnation point instead of placing at rear stagnation point. The reduction of drag and lift coefficient are directly proportional to thorn length and thorn inclination angle. It is found that the drag and lift are minimized by 16% & 46% for Re = 100 respectively, and 22% & 60% for Re = 180 compared to a square model (without thorn).