1. Aerodynamic Force Measurement
Yezad Anklesaria Graduate Student Aerospace Engineering Office: Toomey Hall 212 GTA- ME 242
Wednesday 13 February 2013

2. Overview Objective Wind tunnels and experimental equipment
Experimental setup, procedure and measurements
Momentum equation and drag
Wake
Expected Results
Examples
Reference

3. Purpose of Experiment
Gain experience with setting up and performing aerodynamic experiment
Learn some basic concepts in aerodynamic force measurement
Gain experience with flow visualization
Gain hands-on experience with common instrumentation used in the aerodynamic experiments

4. Wind Tunnel

5. Types of Wind Tunnel Test Section Speed Closed loop Open loop
Low speed wind tunnel (0.3 > M)
High Speed wind tunnels (0.4 < M < 0.75)
Transonic wind tunnel (0.75 < M < 1.2)
Super sonic wind tunnels (1.2 < M < 5)
Hypersonic wind tunnels Mach (5 < M < 15)

6. Experimental Setup

7. Pitot Tube Principle of Operation Bernoulli’s Equation
Stagnation pressure = static pressure + dynamic pressure
P1= Static Pressure
V1= Velocity of Flow
P0= Total pressure
r = Density
Total Pressure
Velocity
Static Pressure

8. Experimental Wing NACA 0015 Airfoil Max. thickness =2.24
Chord: c = 16 inch
Span : b = 16 inch

9. Data Collection Atmospheric data (Temperature and Pressure)
Airfoil at 0o and 2o
Drag
Lift
Velocity at various height
Airfoil at 2o and 20o flap deflection
Flow Visualization

10. Momentum Equation General Form Of Momentum equation
Integral form of momentum equation for steady inviscid flow with no body forces

11. Drag U = Velocity of flow at a given location
U = Free Stream velocity
 = Density Of fluid
v = Velocity of fluid
S = Area of the wing
Cd = Coefficient of Drag

12. Wake Region
A wake is the region of recirculating flow immediately behind a moving solid body, caused by the flow of surrounding fluid around the body.
Wake flow is generally turbulent
As with all wave forms, it spreads outward from the source until its energy is overcome or lost, usually by friction or dispersion.

13. 5o Angle of Attack
10o Angle of Attack
15o Angle of Attack

14. Airfoil in Wind Tunnel

15. Expected Results Drag Calculation using momentum theory
Graphical representation of drag

16. Expected Results Velocity deficit Flow visualization
Plot Velocity deficit to show wake in flow field
Flow visualization
Describe flow at various setups of airfoil

17. Reference and Further Reading
Fundamentals Of Aerodynamics
J. D. Anderson
Similarity Of flows, Pages (40-50) Chapter 1, section 1.8
Equation of Drag, Pages ( ) Chapter 2, section 2.6
Pages ( ) Chapter 3, section 3.3
Wind tunnels Pages ( ) Chapter 3, section 3.3
Pitot Tube Pages ( ) Chapter 3, section 3.4
History Of Wind Tunnels

18. Aerodynamic Testing
Mercedes-Benz SLS AMG Development and Testing Wind tunnel
BMW Aerodynamic Testing

19. Questions