Steady flow over triangular extended solid attached to square cylinder – A method to reduce drag

Numerical analysis of two dimensional steady flows over a triangular extended solid (thorn) attached to square cylinder positioned at front stagnation point and at rear stagnation point separately is reported at low Reynolds number (Re = 40). The variation of thorn length (l′ = 0.2, 0.4 & 0.6) & inclination angle (Θ = 5°, 10°, 15° & 20°) and its effect on the drag, pressure, shear stress, boundary layer as well as on the inertia force and viscous force are of interest. There is comparatively large variation on drag when the thorn is placed at the front side instead of placing at rear. The recirculation length is remained constant by varying the length and inclination of the thorn irrespective of its position. The variation of drag is comparatively less by changing thorn inclination. It is found that the drag is minimized by 2–3% compared to square model

Numerical analysis of drag and lift reduction of square cylinder

AbstractFlow 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)