OIL-FILM INTERFEROMETRY Quantification of aerodynamic performance of riveted and smooth airfoil SHALOM MASANGO, BRENDYN GOODWIN, RYAN SCHAEFER ADVISOR: DR. DURGESH, MENTOR: ANAS NAWAFLEH Acknowledgement: Rodrigo Padilla; wind tunnel setup, testing, and post-processing.
Problem Statement
Wind Tunnel Setup
Daher horizontal tail uses type 4 fasteners which patterned roughness may affect the aerodynamic performance of the horizontal tail.
Measured drag and lift forces for α = ±5.08 degrees at Re = 3 × 105 , α = ±5.08 degrees at Re = 4 × 105 , and α = ±2.52 degrees at Re = 5 × 105 . Lift Force
Value Proposition
Results
Quantify the increase in drag forces of a horizontal stabilizer with riveted and smooth surfaces.
Drag Force Top-Down View
Theory 𝑉𝐿 Reynolds number (𝑅𝑒 = ) is a quantity used to predict the 𝜐
Smooth airfoil Airflow Current Fixture rod Fixture adapter (top) Electronic load cell Fixture adapter (bottom) Stepper motor
fluid flow on the airfoil’s surface. The airfoil chord length (𝐿) and airspeed (𝑉) are changed to maintain similar aerodynamic surface conditions.
OFI Setup The Oil-Film Interferometry (OFI) experiments determine the coefficient of skin friction of an airfoil in a wind tunnel. The airfoil has a line of oil applied to its leading edge, which is spread by the wind. Dark and light fringes are formed on the surface of the airfoil, which are visible through a camera and light setup. By analyzing these fringes, the coefficient of skin friction can be determined.
Side View
Airfoil Design
Conclusion & Future Work
9-inch chord, 17.5-inch span, 1.08-inch thick (NACA 0012):
The airfoil with type 4 universal head rivets produced more drag
smooth vs. type 4 universal head rivets
than the smooth airfoil. Re = 5 x105
3D resin printed in black acrylic plastic by StrataSys direct manufacturing (~$500 per airfoil)
Additionally, a load cell sensor is used to measure drag and lift forces acting on the airfoil. The airfoil is mounted vertically in a wind tunnel and subjected to a constant velocity. The atmospheric pressure, windspeed, and a targeted Reynolds number are key factors used to simulate real-world conditions on the aircraft.
Smooth Surface
Riveted Surface
Dark & Light Fringes
Increased Drag (%) at 0° 61.8
Increased Drag (%) at 1° 58.0
Increased Drag (%) at 3° 44.7
Perform OFI experiments at different Reynolds numbers to measure skin surface shear stresses and identify cause for increase in the drag. Design a setup to mount on Kodiak aircraft for a full-scale OFI test. Analyze the impact on aircraft efficiency due to riveted horizontal tail airfoil.
2023 Capstone Project