Airfoil in a wind tunnel Thermal Engineering Lab ME-4111 Professor: Eduardo Cabrera Damian Luna - 33509 Yetziel Sandoval – 78820 Alberto Gonzales – 80546 Fernando Fresse – 56319 Jaen Soto – 51080

Outline Introduction and objective definition Experimental Procedure Experimental Results Conclusion Recommendation

Introduction Airfoil is the shape of a wing, blade (of a propeller, rotor or turbine), or sail. The lift on an airfoil is primarily the result of its angle of attack and shape. When oriented at a suitable angle, the airfoil deflects the oncoming air (for fixed-wing aircraft, a downward force), resulting in a force on the airfoil in the direction opposite to the deflection.  NACA airfoils are airfoil shapes for aircraft wings developed by the National Advisory Committee for Aeronautics (NACA).

Objective The objective of the present experiment is the parameterization of a NACA airfoil section in flight condition thru the use of a wind tunnel.

Experimental Procedure Task No 1: Pressure distribution along the airfoil surface The objective of this task is to show the pressure distribution on the upper and lower surface of the airfoil NACA 2415. The procedure to perform this task is as follow: Turn ON the wind tunnel and all the complementary devices. Set the angle of attack to 0 degree. This will remain constant during the experiment. Set the value of the tunnel velocity to 10 m/s (33ft/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 m/s (59ft/s) and 25 m/s (82ft/s).

Experimental Procedure Task No 2: Pressure coefficient along the airfoil surface The objective of this task is to determine the pressure coefficient on the upper and lower surface of the airfoil NACA 2415. The procedure to perform this task is as follow: Turn ON the wind tunnel and all complementary devices. Set the wind tunnel velocity at 25 m/s (82ft/s). This will be kept constant during the experiment. Set angle of attack to -2 degree and wait until computer shows steady values. Record Pressure for all tapings along the airfoil. Repeat all steps for angle of attack of 0 degree and 8 degree.

Experimental Procedure Task No 3: Lift on the airfoil The objective of this task is to determine the effect on lift due to the wind tunnel velocity. The procedure to perform this task is as follow: Turn ON the wind tunnel and all complementary devices. Set the angle of attack to 0 degree. Set the wind tunnel velocity at 10 m/s, and then let the system get steady. Record pressure for all tapings along the airfoil. Change wind velocity at 15 m/s, 20 m/s, and 25 m/s and repeat steps c and d. After you finish with the last velocity, repeat all steps for the angle of attack of 8 degree.

Experimental Procedure Task No 4: Stalling on the airfoil The objective of this task is to find the angle of attack that lead to stall the airfoil NACA 2415. The procedure to perform this task is as follow: Turn ON the wind tunnel and all complementary devices Set the tunnel velocity to 25 m/s. This will be kept constant during the experiment. Set the angle of attack to 10o1 (starting point) and wait until computer shows steady values of pressures on the upper surface of the airfoil. Then increase the angle of attack by 1 degree and observe if there is sudden change of pressure on the upper surface. If not, repeat this step. e) If there is a sudden change on pressure distribution, then record the previous distribution and the following one.

Results

Results

Results

Results

Results

Results

Results

Conclusion It was very important for the group to collect all the data and analyzed and verified the pressure distribution of an airfoil at different points throughout the airfoil. The understanding of the concept of lift is necessary, such when the angle of attack increases; the lift is increased proportionally as well.

Recommendation We should do more tests with different parameters to view how they affect and change results. Make sure after every angle is increased, the velocity remains constant at 25 m/s. Will be very helpful the use of different types of wings in order to compare the results each other and then see the behaviors and have a better understanding of how the geometry of the wing affect the performance of the airfoil.