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1ME425: Aerodynamics1
ME 425: AERODYNAMICS- Dr. A.B.M. Toufique Hasan
Associate Professor Department of Mechanical Engineering,
BUET
Lecture # 1 (Introduction)March 2, 2015
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Aerodynamics is the study of dynamics of gaseous
fluids(air/gas), especially the atmospheric interaction with
movingbodies.
This field of engineering deals with the aerodynamics
forcesnamely lift and drag and moments and the heat transfer
ratesacting on a vehicle in flight.
These mechanical parameters greatly depends on the pattern
offlow around the vehicle.
And the resultant flow pattern depends on the geometry of
thevehicle (shape of the airfoil: NACA, SC, RAE, ONERA, BGK,NLR,
DRA, OAT ), its orientation with respect toundisturbed free stream
(Angle of Attack-AOA), and the speed(Mach No.) and altitude at
which the vehicle is moving.
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Fig. Viscous Flow around a circular cylinder
Fig. Viscous Flow around a square cylinder
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Fig. Flow past an airfoil
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The complete flight of a vehicle/object is mostly comprises
ofthe following matters:
Aerodynamics Propulsion and Power Structural mechanics/dynamics
Stability and control
Aerodynamics is the fundamental of Aerospace engineering. Agreat
scope is available for propulsion technology (Jetpropulsion and
rocketry) and structural dynamics.
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The physics of aerodynamics can be learnt from
Theoretical aerodynamics (governing equations, simplification,
theoretical modeling etc.)
Experimental aerodynamics (wind tunnel, flow visualization-PIV,
instrumentation, measurements etc.)
Computational aerodynamics (governing equations, numerical
techniques, computational resources, CFD)
Several promising commercial software for CFD are- ANSYS FLUENT
ANSYS CFX FASTRAN STAR CCM+ ADINA
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Aerodynamics can be broadly classified to two groups-1. External
aerodynamics 2. Internal aerodynamics
External aerodynamics Internal aerodynamics1. Helicopter2. Civil
aircraft/passenger aircraft3. Cargo aircraft4. Military aircraft
(most advanced)5. Rockets6. UAV7. Spaceships8. Wind turbine9.
Racing car aerodynamics10.High speed train aerodynamics
1. Rocket nozzle (C-D nozzle)2. Compressor/turbine blade3. Fan
blade4. Butterfly valve5. Cascade
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Air Berlin B737-700
B767 climbing in moist air
Lufthansa B737-300
Airbus A380
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First Flight: December 15, 2009The Boeing 787-8 Dreamliner is
asuper-efficient airplane. It will bringthe economics of large jet
transportsto the middle of the market, using 20percent less fuel
than any otherairplane of its size.Cockpit crew: 2Seating: 210 -250
passengersRange 14200 15200 KmEngine (s) - Two GE GENX /TwoRolls
Royces Trent 1000.Cruise speed: 902 Kph. (Mach 0.85)
Dreamliner: world's first major airliner touse composite
materials for most of itsconstruction
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Lockheed Martin F-22A Raptor
A-10 Thunderbolt II
Avro Vulcan Bombar
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Space Shuttle
Space Shuttle Main Engine
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Ariane 5 just after lift-off
Shock diamonds
Flow structure inside nozzle
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Unmanned air vehicle (UAV)
Flying of bird
UAV is used for Remotely piloted Surveillance Detection of
biological,chemical or nuclear materials
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Vehicles with wing spans less than approximately 6m andmasses
less than 25 kg are usually considered as UAV.
UAV are either remotely piloted or autonomous with
artificialintelligence.
Requirements for a typical low-altitude small UAV include Long
flight duration at speeds between 20 and 100
km/h Cruise altitude 3 to 300 m Light weight All-weather
capabilities
Because of recent availability of very small sensors,
videocamera, and control hardware, systems as small as 15 cmwith
mass of 80 g, referred to as micro-air vehicle (MAV),are now
possible for limited missions.
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The most important parameter in fluid dynamics/aerodynamics
isthe Reynolds number, Re which is the ratio of inertia force
toviscous force.
Fig. Reynolds number range for flight vehicles*
*
http://www.annualreviews.org/doi/pdf/10.1146/annurev.fluid.35.101101.161102
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Fig. Variation of Reynolds numbers with speed acrossinsects,
micro-air vehicles, birds, Model airplanes,Human powered vehicles,
aircraft, hang-gliders andlighter than air airships. Adapted from
(Lissaman 1983)
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NACA 0012
NACA 0015
NACA 0024
NACA 2414
BOEING 737 Root
Boeing 737 Midspan
Boeing 737 Outboard
RAE 2822 (SC)
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Course content1. Aerodynamic forces-drag and lift2. Inviscid
incompressible flow to include potential function,
stream function, circulation3. Basic potential flows4. Kutta
Joukowski theorem5. Airfoil theory6. Wing theory7. Aircraft
propulsion8. Aircraft performance; static and special performance9.
Introduction to stability and control
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Reference texts:1. Fundamentals of Aerodynamics- J Anderson2.
Aerodynamics for Engineers- John J Bertin3. Aerodynamics for
Engineering Students - E. Lo Houghton
and PW Carpenter4. Introduction to Flight - J Anderson5.
Aircraft performance and Design - J Anderson