Browsing by Author "Alonge, O. I."
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Item DELAY OF CATASTROPHIC BOUNDARY LAYER SEPARATION OVER NACA 23012 AIRFOIL; A NUMERICAL STUDY(1st International Conference on Engineering and Environmental Sciences, Osun State University., 2019) Julius, M.O.; Alonge, O. I.Flow separation is caused by the action of the combined effect of the adverse pressure gradient and viscous force on the surface of the aeroplane wing and these lead to enormous loss of energy. Consequently, the aerodynamic performance is adversely affected (i.e. there is lift reduction and drag enhancement) and may lead to a catastrophe which put the safety of the aeroplane and the lives on it in danger. The introduction of suction slots, flaps, sophisticated high lifting devices to control the flow through separation delay can mitigate the aerodynamic losses. Therefore, this paper focuses on using a perpendicular suction to control the boundary layer separation of flow over the NACA 23012 aerofoil in order to stem the stalling effect that may lead to fatality. This was achieved by careful design and optimisation of the suction positions, suction jet amplitudes and other geometric parameters. The Reynolds Average Navier-Stokes (RANS) equations were employed together with the Menter’s shear stress turbulent model. The jet with of 2.5% of the chord length was placed at different position varied from 10% to 70% of the chord length; the jet velocity was varied from 0.1 to 0.3 of the free stream velocity. The result of this study demonstrated that when the jet position is moved towards the trailing edge the lift to drag ratio decreases. Also, as the jet amplitude was increased, the lift to drag ratio increased commensurately. The jet position of 0.2c and jet amplitude of 0.3 is the most effective to improve the lift to drag ratio when compared to the NACA 23012 without suction. So the point of separation is delayed and the lift is increased significantly.Item The Effects of Heat Generation on Cutting Tool and Machined Workpiece(International Conference on Engineering for Sustainable World, 2019) Ogedengbe, T.S.; Okediji, A. P.; Yussouf, A. A.; Aderoba, O. A.; Abiola, O. A.; Alabi, I. O.; Alonge, O. I.Metal cutting processes usually cause heat generation at the cutting zone (around the workpiece-tool intersection). The heat generated during these processes may cause different effects on both the workpiece and tool, this in turn may affect the finished product and the general performance of the machined piece. In this study, a review was done on various types of machining conditions available, effects of heat generated on the workpiece and tool, and the approaches adopted to reduce this heat at cutting zones. This study also focuses on the simulation of percentage ratio of heat removal. To handle the simulation, various approaches of heat removal methods were used to get the percentage ratio using the ansys version 19.1 software. It was discovered that heat generation causes two major types of wear on the tool, crater and flank wear, resulting in the reduction of cutting tool life as well as dimensional inaccuracy, surface damage and severe corrosion cases on the workpiece. Various heat reduction methods and coolant application types were as well studied and their merits and demerits were discussed.Item STALL CONTROL ON THE NACA 23012 AIRFOIL VIA SINGLE AND DOUBLE SUCTION(1st International Conference on Engineering and Environmental Sciences, Osun State University, 2019-11) Alonge, O. I.; Akinneye, A.O.; Julius, M. OFlow separation due to adverse pressure gradients is the driving agent for the stalling of wings and consequently aircraft which may lead to disaster. Therefore, this paper focuses on the control of the negative effects of stall on the aerodynamic performance of a NACA 23012 airfoil through the implementation of suction on the upper surface of the airfoil. The suction is carried out at a Reynolds number of 𝑅𝑒=6×106, at angles of attack from 0º to the critical angle. Considering the suction position, and the suction width for a single suction, the capability of suction to control stall is studied. Also, double suction was implemented to determine the effect of multiple slots. The numerical analysis was carried out using the Reynolds Averaged Navier-Stokes equations (RANS) in conjunction with the k-omega (SST) turbulent model. The results from this investigation show that suction is more effective closer to the leading edge by boosting lift by as much as 25% and reducing drag by over 70%. The use of double suction offered no improvements over single suction other than extending the critical angle of attack to 28 º.