1. Airfoil in a Wind Tunnel
Sean Crespo #80774
Prof: Eduardo Cabrera Me

2. Outline Introduction and Objective Definition Experimental Procedure
Experimental Result
Conclusion
Recommendations

3. Introduction and Objective Definition
We will use a wind tunnel to explore the effect of lift and drag on an airfoil, explore how the angle of attack changes the amount of lift that the airfoil experiences. study the effects of velocity on lift and how the shapes play a huge role on the amount of lift and drag generated on the airfoil. Analyze also the pressure distribution on the upper and lower surface of the airfoil.
The objective of this experiment is measure the Aerodynamic Forces and visualize the fluid properties behavior at an airfoil Under wind tunnel conditions.

4. Interface

5. Experimental Procedure
Step 1: Pressure distribution on the upper and lower surface of the airfoil
Turn ON the wind tunnel and all the complementary devices
Set the angle of attack to zero degrees. This will remain constant during the experiment.
Set the value of the tunnel velocity to 10 m/s, and wait until computer shows steady values.
Record pressure for all tapings along the airfoil.
Repeat all steps for wind tunnel velocities of 18 and 25 m/s.
Set the tunnel velocity to 25 m/s. This will be kept constant during the experiment.
Set the angle of attack to -2 and wait until computer shows steady values.
Repeat all steps for angles of attack of 0, 8 degrees.
Step 2: Pressure coefficient on the upper and lower surface of the airfoil

6. Experimental Procedure
Step 3: lift acting on the airfoil versus the wind velocity
Set the angle of attack to 0.
Set the wind tunnel velocity at 10m/s, and then let the system get steady.
Record pressure for all tapings along the airfoil.
Change wind tunnel velocity at 10 m/s, 15 m/s, 20 m/s and 25 m/s and repeat steps c and d.
After you finish with last velocity, repeat all steps for the angle of attack of 8.
Set the tunnel velocity to 25 m/s. This will be kept constant during the experiment.
Set the angle of attack to 10° and wait until computer shows steady values of pressure on the upper surface of the airfoil.
Then increase the angle of attack by 1°and observe if there is a sudden change of pressure on the upper surface. If not, repeat this step.
Step 4: Angle of attack that lead to stall the airfoil

7. Experimental Results Pressure Coefficient vary at some angle attack.
0 lift at 0 degrees on a symmetric airfoil.

8. Similar behavior between experimental and theoretical data.
Experimental Results
Similar behavior between experimental and theoretical data.

9. Upper and Lower Pressures distribution in function of velocity.
Experimental Results
Upper and Lower Pressures distribution in function of velocity.

10. Because Stall condition, we can get pressure abnormalities.
Experimental Results
Lift in function of velocity at 0 and 8 Deg
Because Stall condition, we can get pressure abnormalities.

11. Conclusion
After carrying out the laboratory and analyzing the data can be observed that Lift is directly proportional to velocity until certain point, for an example for the velocities of 10m/s, 15m/s, 20m/s and 25m/s it was obtained a lifts of 6.67N, 14.48N, N and 39.16N respectively.
If the pressures are also analyzed we can notice that at 0° of angle and a velocity of 25m/s, when at upper side and lower side values of pressures are Pa and Pa
Most of the objectives were successfully accomplished, theory was validated and results validate the theory that states that the distributions of pressures along the airfoil are main factors for the generated lift forces.

12. Recommendations Obstruction of the fan area when it is operating
not be carried out in small area
When the angle of attack is taken should be checked visually because mismatches are likely to occur on the airfoil.