Post on 13-Jul-2016
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Introductionwhy-airplanes-fly-
aerodynamicsDr. Hamdy A. Kandil
Preface Objectives
The course aims to providing the students with fundamental knowledge of aerodynamics. As a core course, it will focus on the basic understanding and engineering approaches to aerodynamics. The students will be introduced to a number of methods, which are routinely used as part of the aircraft design process
Learning Outcome Upon successful completion of the course, the students will:
appreciate governing equations of aerodynamic flows. have a basic understanding of inviscid incompressible flow and basic
airfoil/wing theory have a basic understanding of compressible flows and understanding in
the application to transonic/supersonic flows. appreciate aerodynamic design considerations.
Activities Apply simple superposition of elementary flow solutions to study the flow
around circular cylinders, Joukowski airfoil and general airfoils Compute aerodynamic forces on streamlined bodies, in particular airfoils and
wings in incompressible, subsonic and supersonic flow Introduce students to experimental methods
Textbook & References Text Book
Aerodynamics for Engineers, John J. Bertin & Russell M. Cummings, Pearson, 2014, (6th edition), ISBN 978-0-273-79327-4
References Fundamentals of Aerodynamics, John Anderson, McGraw-Hill, 2011, (5th
edition), ISBN 978-0-07-339810-5. Aerodynamics for Engineering Students, E.L. Houghton, P.W. Carpenter,
Steven H. Collicott, Daniel T. Valentine (6th edition), Elsevier, 2013, ISBN: 978-0-08-096632-8
Foundations of Aerodynamics, Arnold M. Kuethe & Chuen-Yen Chow, John Wiley, 1998, 5th edition, ISBN 0-471-12919-4
Basic Aerodynamics Incompressible Flow, Gary A. Flandro, Howard M. McMahon, Robert L. Roach, Cambridge, 2012, ISBN 978-0-521-80582-7
Web Some excellent fluid dynamics movieshttp://web.mit.edu/hml/ncfmf.html ) NASA Aeronautics (http://www.nasa.gov/topics/aeronautics/index.html ) UIUC Applied Aerodynamics Group (http://m-
selig.ae.illinois.edu/index.html )
Course Contents1. Introduction
Role of aerodynamics in aerospace engineering, revision of fluid mechanical principles, fundamental principles
2. Potential Flows Circulation, stream function, potential function, elementary flows, flow
around a cylinder, generation of lift3. Incompressible Flow over Airfoils
Airfoil nomenclature and characteristics, Kutta-condition, thin airfoil theory, airfoil drag, high-lift devices
4. Incompressible Flow over Finite Wings Downwash and induced drag, Biot-Savart law and Helmholtz theorems,
lifting line theory, delta wings5. Compressible Flows
Thermodynamic properties, energy equation, speed of sound, stagnation point properties, sonic conditions, normal shocks, oblique shocks
6. Subsonic and Transonic Flows Linear theory, Prandtl-Glauert factor, critical Mach number, area rule,
supercritical airfoil design7. Supersonic Flows
Principles, shock, expansion theory, linear theory8. Experimental Aerodynamics
DRAG
WEIGHT
THRUST
LIFT
The Four Forces of Flight The forces acting on an airplane in flight are lift, weight, thrust,
and drag. These forces are in equilibrium during straight-and-level, unaccelerated flight.
FORCES ACTING ON AIRCRAFT IN FLIGHT
FORCES ACTING ON AIRCRAFT IN FLIGHT
LIFTActs at right angle to the line of flight & through the Centre of Pressure of the wings
THRUST• The aircraft’s propelling force• Arranged symmetrically to the center line• Acts parallel to the line of flight
DRAG• Opposes the forward
motion• Regarded as a rearward
acting force
WEIGHT@ GRAVITYActs vertically downwards through the Centre of Gravity
PRODUCTION OF LIFT To keep flying
aircraft must produce a
force equal to its own
weight
Greater force – to lift
the aircraft from the
ground
Force (lift) is provided
by the wing
PRODUCTION OF LIFT
Lift is an aerodynamic force
Lift must exceed weight for flight
Generated by motion of aircraft through air
Created by the effects of airflow past wing
Aircraft lift acts through a single point called the center of pressure.
LiftLift is the force created by the interaction between the wings and the airflow. It always act upwards. It is considered to be the 'most important force' as without it, an aircraft cannot ascend from ground and maintain altitude.
Lift: Wing Section
Lift Equation: L=CL × ½ ρ × A × V2
Angle of Attack The angle of attack is the angle between the chord
line and the average relative wind.
Greater angle of attack creates more lift (up to a point).
Pressure Field
Result of the accelerated flow on top and decelerated flow on bottom.
high
low
High velocity
Low pressure
Low velocity
High pressure
Angle of Attack and Lift Force
Flow structure on an airfoil
AIRFOIL STALLAttached flow
Lift Relates to AOA
Zero Lift at Zero AOAForce Lift
That’s Why Airplanes Fly.
DO YOU NEED WINGS TO FLY?
One Wing Landing
Weight
Weight is not constant
Varies with passengers, cargo, fuel load
Decreases as fuel is consumed or payload off-loaded
Direction is constant toward earth’s center
Acts through a single point called the center of gravity (the CG)
This force acts on an aircraft due to the aircraft's body weight and Earth's gravity. Weight is a downward force.
This force is created by an aircraft's engine and is required for forward motion.
Forward-acting force opposes drag Direction of thrust depends on design Propulsion systems produce thrust Equal to drag in straight, constant speed flight
Thrust
Drag
An aerodynamic force. Resists forward motion. Increases with the square of speed. Two broad drag classifications.
Friction drag: drag created by airplane surface.A result of air viscosity.
Pressure (Form) drag: drag created by pressure difference.Caused by the airplane geometry.
This force acts in reverse direction to motion and hinders forward motion. Drag is considered as a negative force and all engineers try their best to reduce drag.
Drag Equation: D=CD × ½ ρ × A × V2
Axis of Roll (Longitudinal Axis)
Axis of Pitch (Lateral Axis)
Axis of Yaw (Vertical Axis)
Three Axes of Movement
Flap
Flap
Spoiler
Spoiler
Flight Control Surfaces
Pitch Around the Lateral Axis
The ELEVATOR controls PITCH. On the horizontal tail surface, the elevator tilts up or down, decreasing or increasing lift on the tail. This tilts the nose of the airplane up and down.
Elevator Controls Pitch
Roll Around Longitudinal Axis
Ailerons Control RollThe AILERONS control ROLL. On the outer rear edge of each wing, the two ailerons move in opposite directions, up and down, decreasing lift on one wing while increasing it on the other. This causes the airplane to roll to the left or right.
Yaw Around the vertical Axis
The RUDDER controls YAW. On the vertical tail fin, the rudder swivels from side to side, pushing the tail in a left or right direction. A pilot usually uses the rudder along with the ailerons to turn the airplane.
Rudder Controls Yaw
Some of the people you’ll get to know …
Leonhard Euler
Source: \\www.phdtree.org
Ph.D. Tree of Hamdy Kandil
ODU 1993
VPI 1974
Stanford 1964
Cal Tech 1949
Princeton 1942
Free U of Berlin 1921
U of Göttingen 1905
U of Königsberg 1885
U of Erlangen-Nuremberg 1873
U of Bonn 1868
U of Munich 1899U of Göttingen
University of Leipzig 1886
U of Basel 1694
U of Basel 1676
U of Basel 1726
1756
École Normale Supérieure Paris 1800
U of Bonn 1827
U of Bonn 1853
U of Helmstedt1799
U of Marburg 1823
U of Göttingen1812
U of Göttingen1786