It is a fact of common experience that a body in motion through a fluid experience a resultant force which, in most cases is mainly a resistance to the motion. A class of body exists, However for which the component of the resultant force normal to the direction to the motion is many time greater than the component resisting the motion, and the possibility of the flight of an airplane depends on the use of the body of this class for wing structure. Air foil is such an aerodynamic shape that when it moves through air, the air is split and passes above and below the wing. The wing’s upper surface is shaped so the air rushing over the top speeds up and stretches out. This decreases the air pressure above the wing. The air flowing below the wing moves in a comparatively straighter line, so its speed and air pressure remain the same. Since high air pressure always moves toward low air pressure, the air below the wing pushes upward toward the air above the wing. The wing is in the middle, and the whole wing is “lifted.” The faster an airplane moves, the more lift there is. And when the force of lift is greater than the force of gravity, the airplane is able to fly.
An air foil is a body of such a shape that when it is placed in an air-streams, it produces an aerodynamic force. This force is used for different purposes such as the cross sections of wings, propeller blades, windmill blades, compressor and turbine blades in a jet engine, and hydrofoils are examples of airfoils. The basic geometry of an airfoil is shown in Figure.
The leading edge is the point at the front of the airfoil that has maximum curvature.
The trailing edge is defined similarly as the point of maximum curvature at the rear of the aerofoil.
The chord line is a straight line connecting the leading and trailing edges of the aerofoil. The chord length, or simply chord is the length of the chord line and is the characteristic dimension of the aerofoil section.
Design A NACA2412/4 Digit Profile
Generate A coordinates Of NACA 2412 Profile Where Max. Camber = 2% , Chord = 0.4 And Max.Thickness is 12% So as per this criteria we get coordinates as below,
This Profile Is generated through Co-ordinates Which are taken from aerofoil Tool as Shown in above topic With Ansys Design Modeler.
In order to analyse fluid flow, flow domains are split into smaller sub domains. The governing equations are then discretised and solved inside each of these sub domains. The meshed area around the aerofoil is shown in below figure in which meshing accuracy is increasing as we are go towards the aerofoil.
- Co efficient Of Drag
The drag equation, Fd=1/2⋅ρ⋅v^2⋅Cd⋅A so co efficient of drag is given by the, Cd= (2Fd)/(ρ⋅v^2 A) is essentially a statement that the drag force on any object is proportional to the density of the fluid and proportional to the square of the relative speed between the object and the fluid. In fluid dynamics the Cd is a dimensionless quantity that is used to quantify the drag or resistance of an object in a fluid environment such as air or water.
- Coefficient Of Lift
A fluid flowing past the surface of a body exerts a force on it. Lift is the component of this force that is perpendicular to the oncoming flow direction. It contrasts with the drag force, which is the component of the surface force parallel to the flow direction. If the fluid is air, the force is called an aerodynamic force. The lift equation, L = 1/2⋅ρ⋅v^2⋅Cl⋅A Then , Cl = 2L/(ρ⋅v^2 A)
This work is done by Tajagna Vyas as a purpose of Practice.