Drag and Lift E 80 Fluid Measurements Spring

Drag and Lift E 80 Fluid Measurements Spring 2009

Forces on a Rocket http: //www. grc. nasa. gov/WWW/K-12/rocket/rktfor. html

The Question • In the event of a crash landing of your rocket, what will be the effect on the instruments inside the rocket? (Translation) • What is the velocity of impact? • What is the impulse response of the rocket structure?

Aerodynamic Forces What force does a moving fluid exert on a solid body immersed in the fluid? At any point on surface:

Aerodynamic Forces Integrate pressure and shear stress distributions around body surface Drag FD - component of resultant force in direction of flow Lift FL - component of resultant force perpendicular to direction of flow

The Wind Tunnel

LVDT Displacement Sensors http: //www. macrosensors. com/lvdt_macro_sensors

Pitot Static Tube

Venturi Effect http: //en. wikipedia. org/wiki/Venturi_effect

One Dimensional Flow

Pitot Static Tube • At A • At B

Newton’s Hypothesis “Pressure” Drag

Viscous Boundary Layer “Skin Friction” Drag

Dimensional Analysis • 5 variables, 3 dimensions (mass, length, time) => 2 dimensionless groups

Dimensional Analysis Define: Drag Coefficient Reynolds Number

Dimensional Analysis Similarly define: Lift Coefficient

Cd Values

Lift Coefficient of Airfoil

http: //www. aquaphoenix. com/lecture/ideas-flow/

Wave Drag http: //aerorocket. com/Visual. CFD/IMAGES/

The Wind Tunnel

Pitot Calibration

Drag and Lift Measurements

E 80 Fluid Measurements Lab 1. Calibrate Wind Tunnel Pitot Tube 2. Measure Drag Coefficient of Two Spheres (smooth surface, rough surface). Compare to Literature Values 3. Measure Drag and Lift Coefficients for scaled rocket as a function of angle of attack. Compare to Literature Values 4. Calibrate the pitot tube on the nose cone of your rocket. 5. Estimate the impact velocity of your rocket.