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Aircraft
Published in Milica Kalić, Slavica Dožić, Danica Babić, Introduction to the Air Transport System, 2022
Milica Kalić, Slavica Dožić, Danica Babić
If the wing is cut with a plane that is parallel to the direction of the air flow and perpendiculars to the horizontal plane, an aerofoil is obtained. In other words, the cross section of the wing is the aerofoil. An aerofoil represents an aerodynamically shaped body that produces an aerodynamic reaction (lift) perpendicular to its direction of motion, for a small resistance (drag) force on that plane. An aerofoil is defined by the suction surface (camber upper surface), pressure surface (camber lower surface), the leading edge, the trailing edge, and the chord line, Figure 2.3. The chord is defined as the distance from the leading edge to the trailing edge and generally varies along the span (McCormick 1995). The leading edge is the first point of the aerofoil or the wing line that the air flow encounters. One part of the air flow passes over the upper and the other below the lower surface. The shape of the aerofoil takes advantage of the air’s response to certain physical laws. Because of the aerofoil shape, the air flow rate is higher on the camber upper surface of the wing due to the longer the distance that it crosses. Therefore, an area of lower pressure relative to the camber’s lower surface is produced on the camber’s upper surface. The lift force is a result not only of pressure differences between upper and lower wing surfaces, but also of the angle of air stream attack, aerofoil shape, air density, and air stream velocity.
Axial Flow Pumps
Published in Getu Hailu, Michal Varchola, Peter Hlbocan, Design of Hydrodynamic Machines, 2022
Getu Hailu, Michal Varchola, Peter Hlbocan
It is noted that the area A=bl is the maximum projected area of the airfoil. The lift and drag coefficients are affected by the airfoil profile, the angle of attack α, and the aspect ratio. Their values have been determined experimentally for a great number of profiles. The ratio of the length of the airfoil to the length of the chord is called the aspect ratio. The value of CD is small compared to the value of CL (Figure 4.7). The angle of attack is the angle formed by the chord line and the fluid direction, and it has a significant impact on the drag coefficient.
Force-System Resultants and Equilibrium
Published in Richard C. Dorf, The Engineering Handbook, 2018
line perpendicular to the chord line. Thickness is usually expressed as a percentage of the chord (e.g., a 12% thick airfoil has a maximum thickness of 12% of the chord). The mean camber line is the locus of points halfway between the upper and lower surfaces. The variation of the thickness along the mean camber line is termed the thickness distribution. Camber of the airfoil is defined as the maximum distance between the mean camber line and the chord line in a direction perpendicular to the chord line. When a fluid is moving past the airfoil, the angle of attack is defined as the angle between the freestream velocity and the chord line, denoted as α in Figure 193.6.
Techno-economic analysis of In-stream technology: A review
Published in International Journal of Green Energy, 2023
Upendra Bajpai, Sunil Kumar Singal
Chord length: - The chord length is the distance between the trailing edge and leading edge of an aerofoil. By increasing the chord of the blade, solidity increases, resulting in high starting torque and low power coefficient (Yosry et al. 2021). Hwang, Han Lee, and Jo Kim (2009) also reported a decrement in the power coefficient with an increment in cord length, as shown in Figure 16. A long chord length may cause the streamlined shape to break down, resulting in increased drag (Wenlong, Baowei, and Zhaoyong 2013).