aerofoil - Pressure variation over 662015 Aerofoil...

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1 Pressure variation over 66 2 015 Aerofoil J.Yudhisthir and V.Mourya Indian Institute of Space Science and Technology, Trivandrum, Kerala, 695547 K.Vishnu Teja Reddy Indian Institute of Space Science and Technology, Trivandrum, Kerala, 695547 Yamin Ahmed Noor Indian Institute of Space Science and Technology, Trivandrum, Kerala, 695547 B.N.V.Sai Aditya Indian Institute of Space Science and Technology, Trivandrum, Kerala, 695547 Yash Gupta Indian Institute of Space Science and Technology, Trivandrum, Kerala, 695547 An experiment testing the effect of varying angles of attack on pressure distribution around a symmetrical airfoil NACA 66 2 015 in subsonic wind tunnel was carried out at Aerodynamics Lab in IIST. Pressure taps are placed at intervals on the airfoil to measure the surface pressures of various angles of attack. Using various non-dimensional constants results were plotted for C d and C l at different Angle of attacks and Reynolds number in the test section. Analysis of the results led to the conclusion that the data agreed with expected theoretical results. Increasing the angle of attack created greater lift and drag until the stall angle was reached. At this point, the airfoil stalled due to the separated flow. This stall resulted in a dramatic loss of lift with an increase in pressure drag. Nomenclature RPM = revolutions per minute C d = drag coefficient C l = lift coefficient c = chord d = dimension of the tube having the flow Re = R eynolds’s number V = velocity of the fluid μ = viscosity of the surface with that fluid i = time index during navigation j = waypoint index K = trailing-edge (TE) non-dimensional angular deflection rate I. Introduction [1] An airplane wing has a special shape called an airfoil. When an air foil is moving relative to the air it generates an aerodynamic force, in a rearward direction at an angle with the direction of relative motion. This aerodynamic force is commonly resolved into two components: Drag is the force component parallel to the direction of relative motion, Lift is the force component perpendicular to the direction of relative motion.
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2 [2] Subsonic flight airfoils have a characteristic shape with a rounded leading edge, followed by a sharp trailing edge, with symmetric or asymmetric curvature of upper and lower surfaces. Two sources of aerodynamic forces are pressure and stress distribution over an airfoil. Most foil shapes require a positive angle of attack to generate lift, but cambered airfoils can generate lift at zero angle of attack. Figure1. Forces acting on an airfoil [3] [4] Lift is most commonly associated with the wing of a fixed-wing aircraft, although lift is also generated by propellers, kites, helicopter rotors, rudders, sails and keels on sailboats, hydrofoils, wings on auto racing cars, wind turbines, and other streamlined objects. Lift is a result of pressure differences and depends on angle of attack, airfoil shape, air density, and airspeed. The flow conditions also affect lift. Lift is proportional to the density of the air and approximately proportional to the square of the flow speed. Lift also depends on the size of the wing, being
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