The document provides information about conducting wind tunnel experiments for students in grades 8-12. It includes sample experiments such as measuring lift versus angle of attack and lift versus velocity. It also discusses governing equations, flow visualization techniques, how to make measurements, background on why wind tunnels are used, and selected references for further reading.

1. Wind Tunnel Experiments for Grades 8 - 12 Dr. Judy Foss Van Zante Dynacs Engineering Co., Inc. Cleveland, OH 6/15/99

2. Contents Sample Experiments 3 Governing Equations 15 Flow Visualization Techniques 19 How to Make the Measurements 24 Background - Why Test in Wind Tunnels 27 Selected References 31

3. Sample Experiments

5. Wind Tunnel Test Section with Airfoil Mounting Options Airfoil on Sting Wall-Mounted Flow

6. Lift vs. Angle of Attack As the angle of attack increases, so should the lift - until a certain point (the stall angle of attack). Angle of attack (  ): angle between flow and chord line. Chord line: straight line between most forward and most aft points Lift Flow  

7. Lift vs. Angle (cont.) Angle Lift Visual: See airfoil lift as angle increases Measure: airfoil lift as a function of angle scale

8. Wind Tunnel Experiment Lift vs. Angle Worksheet

9. Lift vs. Velocity As the velocity (speed) increases, so should the lift. Note: Keep the angle of attack constant. The greater the angle (prior to stall) the greater the change in lift. Lift Velocity (Speed)

10. Lift vs. (Velocity) 2 Visual: See airfoil lift as speed increases Measure: airfoil lift as a function of speed Velocity Lift scale V 2 L

11. Wind Tunnel Experiment Lift vs. Velocity Worksheet

13. Wind Tunnel with Drag Objects Mounting Options Bluff Bodies Race Cars Rotating Sting Pulley

15. Governing Equations

19. Flow Visualization Techniques

22. Yarn Tufts on surface Tuft Probe Delta Wing Trailing Edge Cone Flow Visualization Techniques Illustrated x x x x x x x x x x x x x x x x x x x x Tuft Grid

24. How to Make the Measurements

27. Background Why Test in Wind Tunnels?

29. Two of NASA’s Wind Tunnels Ames 80’ x 120’ Langley