lecture aerodynamics aerodynamics

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Introduction why-airplanes-fly- aerodynamics Dr. 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

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Page 1: Lecture Aerodynamics Aerodynamics

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

Page 2: Lecture Aerodynamics Aerodynamics

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

Page 3: Lecture Aerodynamics 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

Page 4: Lecture Aerodynamics Aerodynamics

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

Page 5: Lecture Aerodynamics Aerodynamics

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

Page 6: Lecture Aerodynamics Aerodynamics

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

Page 7: Lecture Aerodynamics Aerodynamics

High velocity

Low pressure

Low velocity

High pressure

Angle of Attack and Lift Force

Flow structure on an airfoil

AIRFOIL STALLAttached flow

Page 8: Lecture Aerodynamics Aerodynamics

Lift Relates to AOA

Zero Lift at Zero AOAForce Lift

That’s Why Airplanes Fly.

Page 9: Lecture Aerodynamics Aerodynamics

DO YOU NEED WINGS TO FLY?

One Wing Landing

Page 10: Lecture Aerodynamics Aerodynamics

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

Page 11: Lecture Aerodynamics Aerodynamics

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

Page 12: Lecture Aerodynamics Aerodynamics

Flap

Flap

Spoiler

Spoiler

Flight Control Surfaces

Pitch Around the Lateral Axis

Page 13: Lecture Aerodynamics Aerodynamics

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

Page 14: Lecture Aerodynamics Aerodynamics

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

Page 15: Lecture Aerodynamics Aerodynamics

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

Page 16: Lecture Aerodynamics Aerodynamics

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