Flow over an airfoil

FLOW OVER AN AEROFOIL

AIM:

1. Model the flow over a NACA0017 airfoil.
2. For the angle of attacks 0,2,4,6,8,10 compare the lift and drag forces.

THEORY:

The NACA airfoils are airfoil shapes for aircraft wings developed by the National Advisory Committee of Aeronautics (NACA). The shape of the NACA airfoils is described using a series of digits following the word "NACA". The parameters in the numerical code can be entered into equations to precisely generate the cross-section of the airfoil and calculate its properties.

• Leading-edge: The front edge of an airfoil
• Trailing edge: The rearmost edge of an airfoil
• Chord: The length of the chord line from leading edge to trailing edge
• Chord line: A straight line intersecting leading and trailing edges of the airfoil
• Mean camber line: A line drawn halfway between the upper and lower surfaces of the airfoil

The NACA four-digit wing sections define the profile by:

1. First digit describing maximum camber as a percentage of the chord.
2. The second digit describing the distance of maximum camber from the airfoil leading edge in tenths of the chord.
3. Last two digits describing the maximum thickness of the airfoil as a percent of the chord.

The NACA 0017 airfoil is symmetrical, the 00 indicating that it has no camber. The 17 indicates that the airfoil has a 17% thickness to chord length ratio: it is 17% as thick as it is long.

SPECIFICATION:

Fluid - Air

Flow - External Flow

Pressure and velocity of aerofoil vary at different angles of attack - 0, 2, 4, 6, 8, and 10.

Velocity in x-direction - 600 m/s

Gravity - Not considered

Surface roughness - 0

For the angle of attack at 0:

• Velocity flow

• Pressure flow

For angle of attack at 2:

• Velocity flow

• Pressure flow

For the angle of attack at 4:

• Velocity flow

• Pressure flow

For the angle of attack at 6:

• Velocity flow

• Pressure flow

For the angle of attack at 8:

• Velocity flow

• Pressure flow

For the angle of attack at 8:

• Velocity flow

• Pressure flow

Forces acting on the aerofoil:

The aerodynamic force is the resultant vector from adding the lift vector, perpendicular to the flow direction, and the drag vector, parallel to the flow direction.

This aerodynamic force is commonly resolved into two components, acting through the body's center of pressure

• Drag is the force component parallel to the direction of relative motion.
• Lift is the force component perpendicular to the direction of relative motion.

For a different angle of attack, the lift and drag forces are calculated.

These are the average values of SG forces in X (drag force) and Y(lift force) directions.