Flow over an airfoil

Aim: - Model the flow over a NACA0017 airfoil and compare the lift and drag forces for different angle of attack

Theroy : -

• The NACA airfoils are airfoil shapes for aircraft wings developed by the National Advisory Committee for Aeronautics (NACA). The shape of the NACA airfoils is described using a series of digits following the word "NACA".
• Angle of attack is the angle between a reference line on a body (often the chord line of an airfoil) and the vector representing the relative motion between the body and the fluid through which it is moving. Angle of attack is the angle between the body's reference line and the oncoming flow.
• The airfoil deflects the oncoming air , resulting in a force on the airfoil in the direction opposite to the deflection. This force is known as aerodynamic force and can be resolved into two components , the component of this force perpendicular to the direction of motion is called lift force . The component parallel to the direction of motion is called drag force.

Procedure

1. Go to insert->curve->curve through XYZ points and then browse your txt file saving the cordinates of naca airfoil
   • Naca_file
2. Select the plane and convert this curve into sketch and close the end points
3. Go to rotate entities and rotate it along origin
4. Extrude the sketch to 0.5m
5. Go to flow simulation
6. select wizard type project name then select units systum to SI then select external flow time dependent , total analysis time 5sec and output step time 1sec , select fluid as air and at last give 600m/s velocity in x direction
7. Edit computational domain select 2D simulation type and then give 10m to ending face -5 in starting face and 5 and -5 to top and bottom face repectively
8. Insert local mesh to the airfoil surface
9. Insert surface goal , select surface goal and add force in x and y direction
10. Run the project and get results

Note : - surface force in x direction (SF force (x)) is the drag force and surface force in y direction (SF force (y)) is the lift force

Results

0 degree attack angle

• Velocity profile
  

• Forces

2 degree attack angle

• Velocity profile

• Forces

4 degrees of attack angle

• Velocity profile
  

• Forces

6 degree attact angle

• Velocity profile

• Forces

8 degree attack angle

• Velocity profile

• Forces

10 degree attack angle

• Velocity profile

• Forces

Observation and conclusion

• Forces

  • Angle of attack	Drag force	Lift force
    0	791.2	112.19
    2	1633.08	2169.74
    4	1836.09	4244.95
    6	2194.67	6281.62
    8	2651.93	8257.12
    10	3331.54	10280.45

• Drag force
  
  • As we increase in the angle of attack the drag force increase

• Lift force
  • As we increase angle of attack the lift force increases

• • As we increase the angle of attack both the lift force and drag force increase but the increase in lift force is much greater than the increse in drag force