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Fluid Mechanics in Aeronautics and Astronautics Marc Williams School of Aeronautics and Astronautics.

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Presentation on theme: "Fluid Mechanics in Aeronautics and Astronautics Marc Williams School of Aeronautics and Astronautics."— Presentation transcript:

1 Fluid Mechanics in Aeronautics and Astronautics Marc Williams School of Aeronautics and Astronautics

2 Aeronautics = Airplanes

3 Astronautics = Spacecraft

4 Parts of Aero & Astro Aerodynamics Design Dynamics & Control Structures Propulsion

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6 Three forces from fluids LIFT - Force perpendicular to flight direction The Air pushes the airplane “up” DRAG - Force opposite the flight direction The Air pushes the airplane “back” THRUST - Force in the flight direction Internal pressure inside the engine pushes the aircraft/rocket forward

7 LIFT Newton say : The air pushes the airplane up So The airplane pushes the air down

8 Cessna Citation

9 Boeing 777

10 Boeing 757

11 DRAG The air sticks to the airplane, pushing it back (Viscosity== Friction drag) The airplane imparts kinetic energy to the air behind it…. This energy comes from the engines, And shows up as a drag (Induced Drag, or Drag due to Lift)

12 Flight Regimes – A Vocabulary 0 0 1.0 2.0 3.0 6.0 Mach Number – M Altitude (1000 ft.) 100 80 60 40 20 Subsonic Supersonic Hypersonic Structural Limit (Dynamic pressure and heating) Aerodynamic Limit Transonic V = flight speed a = speed of sound M = V / a

13 Wing Loading (N/m 2 ) All the Worlds Flyers Flyers meeting MAV requirements abound in nature Flyers with most remarkable performance leverage unsteady aerodynamics Flapping provides access to game-changing aerodynamic mechanisms for meeting MAV requirements Conventional Aircraft (Steady) Large Birds (Quasi-steady) Small Birds (Transition) Insects/Hummingbirds (Unsteady) Cruising Speed (m/s) Weight (N)

14 Micro Air Vehicles (MAVs) Unmanned aerial systems becoming for missions too dull, dirty, dangerous, or difficult for pilots – Persistent ISR – Chemical/biological sensing – “Over the hill”/“Around the corner” scouting Operation space is changing – Urban canyons – Building interiors – Subterranean caverns/bunkers MAVs are new class of vehicle to fill new operational roles Images from wikipedia.org, defense-update.com, delta.tudelft.nl

15 DYNAMICS AND CONTROL http://www.grc.nasa.gov/WWW/K-12/airplane/alr.html

16 Mach Number Effects Mach Number = Speed / Speed of Sound Speed of Sound = 340 m/s = 770 mph Mach squared = Kinetic Energy / Thermal Energy

17 An F/A-18 Hornet at transonic speedF/A-18 Hornettransonic

18 F4 phantom ii breaking the sound barrier

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20 Mars Exploration RoverMars Exploration Rover (MER) aeroshell, artistic rendition

21 Thrust Thrust is produced by throwing something opposite to the direction you want to go (Newton again) You can throw air You can throw hot exhaust gases You can throw rocks… but fluids are easier to work with

22 Air Thrower

23 http://www.youtube.com/watch?v=nSQzvimD3cc Turbofan Engine This throws air and hot exhaust gases

24 Turbofan Flowpath

25 Tomahawk Cruise Missile

26 Mi-24 Hind Military Aviation Helicopter Air Thrower

27 Joint Strike Fighter- Marine Version Lift Fan Another Air Thrower

28 OSPREY- Tilt Rotor And another… but you get to change the throw direction

29 Rockets – Pure Hot Gas Throwers

30 How a Rocket Produces Thrust

31 ROCKETS BIG (SSME)

32 A micro-thruster array measuring one-quarter the size of a penny, designed by a TRW-led team for use on micro-, nano- and pico-satellites, has successfully demonstrated its functionality in a live fire test aboard a Scorpius sub-orbital sounding rocket. Individual micro-electromechanical system (MEMS) thrusters, each a poppy seed-sized cell fueled with lead styphnate propellant, fired more than 20 times at 1-second Intervals during the test staged at the White Sands Missile Range. Each thruster delivered 10(-4) Newton seconds of impulse. ROCKETS: SMALL

33 Sidewinder Air to Air supersonic missile

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35 THE END Have a great summer

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37 Dynamic Stall on an Airfoil

38 Boeing 757

39 Vortex break-up on a delta wing at high incidence

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