me 425: aerodynamics - toufiquehasan.buet.ac.bd 2016-lecture 1.pdf · • ansys fluent (me, buet...
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ME425: Aerodynamics1
ME 425: Aerodynamics
Dr. A.B.M. Toufique Hasan
Associate Professor
Department of Mechanical Engineering, BUET
Term: July 2016
04 September 2016
Lecture-1: Introduction
http://teacher.buet.ac.bd/toufiquehasan/courses.php
ME425: Aerodynamics2
Introduction
Aerodynamics is the study of dynamics of gaseous fluids (air/gas),
especially the atmospheric interaction with moving bodies.
This field of engineering deals with the aerodynamic forces namely lift and
drag and moments and the heat transfer rates acting on a vehicle in flight.
These mechanical parameters greatly depends on the pattern of flow
around the vehicle.
And the resultant flow pattern depends on the geometry of the vehicle
(shape of the airfoil: NACA, SC, RAE, ONERA, BGK, NLR, DRA, OAT…
…), its orientation with respect to undisturbed free stream (angle of
attack-AOA), and the speed (Mach No.) and altitude (density) at which
the vehicle is moving.
Multi-element airfoilWing
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ME425: Aerodynamics3
Introduction contd…
Fig. Viscous Flow around a circular cylinder at Re~300 (CFD)
Fig. Laser-induced-fluorescence (LIF) flow visualizations of wake past a circular cylinder at Re~650Source: Journal of Fluid Mechanics 2005; pp-215-252
Fig. Vortex shedding in side-by-side cylindersJournal of Fluid Mechanics 2014; pp-552-576
Fig. Vortex shedding from a square cylinders at Re~90Journal of Fluid Mechanics 2007; pp-169-178
Re ~100
Vortex street
ME425: Aerodynamics4
Introduction contd…
Fig. Flow past an airfoil
Fig. Separation bubble from SD7003 airfoil at Re=66000Journal of Fluid Mechanics 2009; pp-129-153
streamlines
Chord line
AOA
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ME425: Aerodynamics5
Introduction contd…
The complete flight of a vehicle/object is mostly comprises of the following
matters:
• Aerodynamics
• Propulsion and Power
• Structural mechanics/dynamics
• Stability and control
Aerodynamics is the fundamental of aerospace engineering (aeronautics).
A great scope is available for propulsion technology (Jet propulsion and
rocketry) and structural dynamics.
ME425: Aerodynamics6
Introduction contd…
The physics of aerodynamics can be learnt from
• Theoretical aerodynamics (governing equations, simplification, theoretical modeling etc.)
• Experimental aerodynamics (wind tunnel, flow visualization-PIV, LIF, Schlieren, instrumentation, measurements etc.). ME, BUET has subsonic and supersonic (M~2.0) wind tunnels.
• Computational aerodynamics (governing equations, numerical techniques, computational resources, CFD)
Since the powerful computers are available now-a-days, aerodynamicproblems are conveniently solved using CFD software, such as
• ANSYS FLUENT (ME, BUET has licence)
• ANSYS CFX
• FASTRAN
• STAR CCM+
• ADINA
This course (ME 425) will cover the basics of aerodynamics based ontheoretical approach (theoretical aerodynamics).
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ME425: Aerodynamics7
Introduction contd…
ME425: Aerodynamics8
Introduction contd…
Aerodynamics can be broadly classified to two groups-
1. External aerodynamics
2. Internal aerodynamics
External aerodynamics Internal aerodynamics
1. Helicopter
2. Civil aircraft/passenger aircraft
3. Cargo aircraft
4. Military aircraft (most advanced)
5. Rockets
6. UAV
7. Spaceships
8. Wind turbine
9. Racing car aerodynamics
10. High speed train aerodynamics
1. Rocket nozzle (C-D nozzle)
2. Compressor/turbine blade
3. Fan blade
4. Butterfly valve
5. Cascade
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ME425: Aerodynamics9
Introduction contd…
Air Berlin B737-700
B767 climbing in moist air
Lufthansa B737-300
Airbus A380
ME425: Aerodynamics10
Introduction contd…
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ME425: Aerodynamics11
Introduction contd…
ME425: Aerodynamics12
Introduction contd…
First Flight: December 15, 2009
The Boeing 787-8 Dreamliner is asuper-efficient airplane. It will bring theeconomics of large jet transports to themiddle of the market, using 20 percentless fuel than any other airplane of itssize.
Cockpit crew: 2
Seating: 210 -250 passengers
Range 14200 – 15200 Km
Engine (s) - Two GE GENX /Two RollsRoyce’s Trent 1000.
Cruise speed: 902 Kmph (Mach 0.85)
Dreamliner: world's first major airliner to
use composite materials for most of its
construction
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ME425: Aerodynamics13
Introduction contd…
Lockheed Martin F-22A Raptor
A-10 Thunderbolt II
Avro Vulcan Bombar
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Introduction contd…
Space Shuttle
Space Shuttle Main Engine
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ME425: Aerodynamics15
Introduction contd…
Ariane 5 just after lift-off
Shock diamonds
Flow structure inside nozzle
ME425: Aerodynamics16
Introduction contd…
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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ME425: Aerodynamics17
Introduction contd…
Vehicles with wing spans less than approximately 6m and massesless than 25 kg are usually considered as UAV.
UAV are either remotely piloted or autonomous with artificial intelligence.
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, video camera, andcontrol hardware, systems as small as 15 cm with mass of 80 g, referredto as micro-air vehicle (MAV), are now possible for limited missions.
ME425: Aerodynamics18
Introduction contd…
The most important parameter in fluid dynamics/aerodynamics is theReynolds number, Re which is the ratio of inertia force to viscous force.
Fig. Reynolds number range for flight vehicles*
* http://www.annualreviews.org/doi/pdf/10.1146/annurev.fluid.35.101101.161102
µ
ρVL=Re
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ME425: Aerodynamics19
Introduction contd…
Fig. Variation of Reynolds numbers with speed across insects, micro-airvehicles, birds, Model airplanes, Human powered vehicles, aircraft, hang-gliders and lighter than air airships. Adapted from (Lissaman 1983)
ME425: Aerodynamics20
Introduction contd…
NACA 0012
NACA 0015
NACA 0024
NACA 2414
BOEING 737 Root
Boeing 737 Midspan
Boeing 737 Outboard
RAE 2822 (SC)
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ME425: Aerodynamics21
Course content
1. Aerodynamic forces-drag and lift
2. Inviscid incompressible flow to include potential function, stream function, circulation
3. Basic potential flows
4. Kutta-Joukowski theorem
5. Airfoil theory
6. Wing theory
7. Aircraft propulsion
8. Aircraft performance; static and special performance
9. Introduction to stability and control
ME425: Aerodynamics22
Reference texts:
1. Fundamentals of Aerodynamics- J Anderson
2. Aerodynamics for Engineers- John J Bertin
3. Aerodynamics for Engineering Students - E. Lo Houghton and PW Carpenter
4. Introduction to Flight - J Anderson
5. Aircraft performance and Design - J Anderson
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