Understanding Aerodynamics

Much-needed, fresh approach that brings a greater insight into
the physical understanding of aerodynamics

Based on the author's decades of industrial experience
with Boeing, this book helps students and practicing engineers to
gain a greater physical understanding of aerodynamics. Relying on
clear physical arguments and examples, Mclean provides a
much-needed, fresh approach to this sometimes contentious subject
without shying away from addressing "real" aerodynamic situations
as opposed to the oversimplified ones frequently used for
mathematical convenience. Motivated by the belief that engineering
practice is enhanced in the long run by a robust understanding of
the basics as well as real cause-and-effect relationships that lie
behind the theory, he provides intuitive physical interpretations
and explanations, debunking commonly-held misconceptions and
misinterpretations, and building upon the contrasts provided by
wrong explanations to strengthen understanding of the right
ones.

• Provides a refreshing view of aerodynamics that is based on the
  author's decades of industrial experience yet is always
  tied to basic fundamentals.

• Provides intuitive physical interpretations and explanations,
  debunking commonly-held misconceptions and misinterpretations

• Offers new insights to some familiar topics, for example, what
  the Biot-Savart law really means and why it causes so much
  confusion, what "Reynolds number" and
  "incompressible flow" really mean, and a real physical
  explanation for how an airfoil produces lift.

• Addresses "real" aerodynamic situations as opposed to the
  oversimplified ones frequently used for mathematical convenience,
  and omits mathematical details whenever the physical understanding
  can be conveyed without them.

Auteur

Doug Mclean, Boeing Commercial Airplanes, USA
Doug McLean is a Boeing Technical Fellow in the Enabling Technology and Research unit within Aerodynamics Engineering at Boeing Commercial Airplanes. He received a BA in physics from the University of California at Riverside in 1965 and a PhD in aeronautical engineering from Princeton University in 1970. He joined the Boeing Commercial Airplane Group in 1974 and has worked there ever since on a range of problems, both computational and experimental, in the areas of viscous flow, drag reduction, and aerodynamic design. Computer programs he developed for the calculation of three-dimensional boundary layers and swept shock/boundary-layer interactions were in use by wing-design groups at Boeing for many years.

Résumé
Much-needed, fresh approach that brings a greater insight into the physical understanding of aerodynamics Based on the author's decades of industrial experience with Boeing, this book helps students and practicing engineers to gain a greater physical understanding of aerodynamics. Relying on clear physical arguments and examples, Mclean provides a much-needed, fresh approach to this sometimes contentious subject without shying away from addressing "real" aerodynamic situations as opposed to the oversimplified ones frequently used for mathematical convenience. Motivated by the belief that engineering practice is enhanced in the long run by a robust understanding of the basics as well as real cause-and-effect relationships that lie behind the theory, he provides intuitive physical interpretations and explanations, debunking commonly-held misconceptions and misinterpretations, and building upon the contrasts provided by wrong explanations to strengthen understanding of the right ones.

• Provides a refreshing view of aerodynamics that is based on the author's decades of industrial experience yet is always tied to basic fundamentals.
• Provides intuitive physical interpretations and explanations, debunking commonly-held misconceptions and misinterpretations
• Offers new insights to some familiar topics, for example, what the Biot-Savart law really means and why it causes so much confusion, what Reynolds number and incompressible flow really mean, and a real physical explanation for how an airfoil produces lift.
• Addresses "real" aerodynamic situations as opposed to the oversimplified ones frequently used for mathematical convenience, and omits mathematical details whenever the physical understanding can be conveyed without them.

Contenu

Foreword xi

Series Preface xiii

Preface xv

List of Symbols xix

1 Introduction to the Conceptual Landscape 1

2 From Elementary Particles to Aerodynamic Flows 5

3 Continuum Fluid Mechanics and the Navier-Stokes Equations 13

3.1 The Continuum Formulation and Its Range of Validity 13

3.2 Mathematical Formalism 16

3.3 Kinematics: Streamlines, Streaklines, Timelines, and Vorticity 18

3.3.1 Streamlines and Streaklines 18

3.3.2 Streamtubes, Stream Surfaces, and the Stream Function 19

3.3.3 Timelines 22

3.3.4 The Divergence of the Velocity and Green's Theorem 23

3.3.5 Vorticity and Circulation 24

3.3.6 The Velocity Potential in Irrotational Flow 26

3.3.7 Concepts that Arise in Describing the Vorticity Field 26

3.3.8 Velocity Fields Associated with Concentrations of Vorticity 29

3.3.9 The Biot-Savart Law and the Induction Fallacy 31

3.4 The Equations of Motion and their Physical Meaning 33

3.4.1 Continuity of the Flow and Conservation of Mass 34

3.4.2 Forces on Fluid Parcels and Conservation of Momentum 35

3.4.3 Conservation of Energy 36

3.4.4 Constitutive Relations and Boundary Conditions 37

3.4.5 Mathematical Nature of the Equations 37

3.4.6 The Physics as Viewed in the Eulerian Frame 38

3.4.7 The Pseudo-Lagrangian Viewpoint 40

3.5 Cause and Effect, and the Problem of Prediction 40

3.6 The Effects of Viscosity 43

3.7 Turbulence, Reynolds Averaging, and Turbulence Modeling 48

3.8 Important Dynamical Relationships 55

3.8.1 Galilean Invariance, or Independence of Reference Frame 55

3.8.2 Circulation Preservation and the Persistence of Irrotationality 56

3.8.3 Behavior of Vortex Tubes in Inviscid and Viscous Flows 57

3.8.4 Bernoulli Equations and Stagnation Conditions 58

3.8.5 Crocco's Theorem 60

3.9 Dynamic Similarity 60

3.9.1 Compressibility Effects and the Mach Number 63

3.9.2 Viscous Effects and the Reynolds Number 63

3.9.3 Scaling of Pressure Forces: the Dynamic Pressure 64

3.9.4 Consequences of Failing to Match All of the Requirements for Similarity 65

3.10 Incompressible Flow and Potential Flow 66

3.11 Compressible Flow and Shocks 70

3.11.1 Steady 1D Isentropic Flow Theory 71

3.11.2 Relations for Normal and Oblique Shock Waves 74

4 Boundary Layers 79

4.1 Physical Aspects of Boundary-Layer Flows 80

4.1.1 The Basic Sequence: Attachment, Transition, Separation 80

4.1.2 General Development of the Boundary-Layer Flowfield 82

4.1.3 Boundary-Layer Displacement Effect 90

4.1.4 Separation from a Smooth Wall 93

4.2 Boundary-Layer Theory 99

4.2.1 The Boundary-Layer Equations 100

4.2.2 Integrated Momentum Balance in a Boundary Layer 108

4.2.3 The Displacement Effect and Matching with the Outer Flow 110

4.2.4 The Vorticity Budget in a 2D Incompressible Boundary Layer 113

4.2.5 Situations That Violate the Assumptions of Boundary-Layer Theory 114

4.2.6 Summary of Lessons from Boundary-Layer Theory 117

4.3 Flat-Plate Boundary Layers and Other Simplified Cases 117

4.3.1 Flat-Plate Flow 117

4.3.2 2D Boundary-Layer Flows with Similarity 121

4.3.3 Axisymmetric Flow 123

4.3.4 Plane-of-Symmetry and Attachment-Line Boundary Layers 125

4.3.5 Simplifying the Effects of Sweep and Taper in 3D 128

4.4 Transition and Turbulence 130

4.4.1 Boundary-Layer Transition 131

4.4.2 Turbulent Boundary Layers 138

4.5 Control and Prevention of Flow Separation 150

4.5.1 Body Shaping and Pressure Distrib…