Configuration Aerodynamics

Transcription

1 Configuration Aerodynamics William H. Mason Virginia Tech Blacksburg, VA The front cover of the brochure describing the French Exhibit at the Montreal Expo, January 2018

2 W.H. Mason CONTENTS i CONTENTS Configuration Aerodynamics Preface 1. Introduction to Configuration Aerodynamics 1.1 Purpose Examples of innovative concepts Overview of the Material to be Covered What s left out Exercises References Getting Ready for Configuration Aerodynamics: Fluid Mechanics Foundations 2.1 Governing Equations of Fluid Mechanics Derivation of the Governing Equations Conservation of Mass: the Continuity Equation Conservation of Momentum and the Substantial Derivative Energy Equation Boundary Conditions Standard Forms and Terminology of Governing Equations Nondimensionalization Use of Divergence Form Standard Form of the Navier-Stokes Equations: Notation The Gas Dynamics Equation and the Full Potential Equation The Gas Dynamics Equation Derivation of the Classical Gas Dynamics Eqn-Related Energy Equation Full Potential Equation Equivalent Divergence Form and Energy Equation Derivation of another form of the Related Energy Equation Special Cases Small Disturbance Form of the Energy Equation Small Disturbance Expansion of the Full Potential Equation Transonic Small Disturbance Equation Prandtl-Glauert Equation Incompressible Irrotational Flow: Laplace s Equation The Boundary Layer Equations Examples of Zones of Application Mathematical Classification or the Type of PDEs Elaboration on Characteristics 2-41

3 ii CONTENTS 2.9 Requirements for a Complete Problem Formulation Exercises References Drag: An Introduction 3.1 The Importance of Drag Some Different Ways to View Drag - Nomenclature and Concepts Farfield Drag Analysis Induced Drag Program LIDRAG Multiple Lifting Surfaces and Munk's Stagger Theorem Zero Lift Friction and Form Drag Estimation Supersonic Wave Drag: the Farfield Wave Drag Integral and the Area Rule The Leading Edge Suction Concept Trim Drag Current Issues for Drag Calculation using Computational Aerodynamics Exercises References Aircraft Configuration Design Options 4.1 Overview Configuration Architecture Options Wing Sweep Why sweep the wing forward Why Canards? Why a flying wing? Three-surface configurations Slender Wings Variable Sweep Winglets Propulsion System Integration Issues Aircraft Control Significant Recent Configuration Concepts The Blended Wing Body The Strut-Braced Wing The Oblique Wing Morphing Airplanes Decision Issues Design Approaches The role of aerodynamics within the overall design process A concluding comment Exercises References 4-21

4 W.H. Mason Contents iii 5. An Overview of Aerodynamic Design including the use of Computational Aerodynamics 5.1 Introduction Configuration sizing: Aerodynamic Considerations Overview of the specific aerodynamic design tasks Use of computational aerodynamics in aerodynamic design Best practices in solving aerodynamics problems with computers 5.5 A Review of detailed aerodynamic design approaches Analysis vs design Review of the detailed design process, including inverse and optimization Brief overview of 2D design Review of 3D transonic design methods Applications of 3D design methods 5.6 Summary of the status of aerodynamic design Exercises References Subsonic aerodynamics of airfoils and wings 6.1 Introduction Airfoils Program PANEL and other prediction methods: Accuracy/Validation Subsonic Airfoil Aerodynamics Airfoil Selection Wings Use and Accuracy of the VLM method Program VLMpc and the Warren 12 test Case Tornado and AVL Aerodynamics of High Aspect Ratio Wings The relation between airfoils and swept wings Wing/Tail and Canard/Wing Aerodynamics Ground Effects using a VLM code Low Aspect Ratio Slender Wings Exercises References Transonic aerodynamics of airfoils and wings 7.1 Introduction Physical aspects of flow development with Mach number Technology Issues/developments The slotted wall wind tunnel Computational challenges/methods Airfoils NASA Supercritical Airfoils The Divergent Trailing Edge Airfoil Transonic Airfoil Performance: The Korn Equation Design Methods Wings 7-15

5 iv CONTENTS Transonic Transport Wing Concepts The Korn Equation applied to drag prediction on wings Fighter Wing Concepts/Issue Exercises References Aerodynamics of high lift devices/powered lift 8.1 Introduction: Why High Lift? A.M.O. Smith s analysis of the lift: the five considerations 8.3 Types of Trailing Edge Devices Types of Leading edge devices Aerodynamics of Leading and Trailing Edge Devices Computational methods for high lift 8.7 Passive and active boundary layer control Powered lift Configuration Integration issues Exercises References 9. High angle of attack aerodynamics 9.1 Introduction Basic Aerodynamics of Hi-a Longitudinal Lateral/Directional Flight Mechanics of Hi-a C n beta dynamic LCDP: the lateral control departure parameter, The spin Control Effectiveness with angle of attack An Example: Putting it all together, the F Some configuration issues: Amazing Stories Exercises References 9-16 An F-18 spin movie is available from the NASA Dryden web site.

6 W.H. Mason Contents v 10. Supersonic aerodynamics 10.1 Introduction Supersonic Cruise Airplanes The B The SR The XB The TU The Concorde The F-22 (and YF-23) The Challenge for Airplane Design Wave Drag A curious story: Multiple Bodies to Reduce Wave Drag and Favorable Interference Planar wing wave drag Wings: lift and drag due to lift Arrow wings and conical camber Modified arrow wings The aerodynamic center shift The Oblique Wing Concept Aero-Propulsion Integration Computational Methods and Supersonic Aerodynamic Design The linear theory starting point Modifications to linear theory: Attainable Thrust Nonlinear aerodynamics of supersonic wings Supersonic Airplane Configuration Design Examples The US SST Story Supersonic Maneuver Wing HSCT and MDO Multidisciplinary Design Optimization, MDO Design to reduce the strength of the sonic boom Modern Efforts Aerion The 2D Supersonic Airfoil Story Sonic QueSST Exercises References Hypersonic aerodynamics 11.1 Introduction Surface pressure estimation Aerodynamic stability and control Aerodynamic Heating Additional Gas Dynamics Considerations High Temperature Gas Dynamics Considerations Hypersonic Vehicle Design 11-25

7 vi CONTENTS Minimum drag axisymmetric shapes at hypersonic speeds Brief review of hypersonic flight vehicles Engine-airframe Integration and Modern Vehicle Development Exercises References Endnote Appendices A. Geometry for Aerodynamicists A.1 Airfoil Geometry A-1 A.2 Classic Bodies of Revolution A-18 A.3 Planform Analysis A-24 A.4 Conical Camber A-29 A.5 Three-Dimensional Wing Geometry A-29 B. Fifteen Minutes of Stealth in Aircraft Design B-1 C. FAR & Mil requirements C-1 D. Examples of aerodynamic design using tools from our software suite. D-1 E. Software for Aerodynamics and Aircraft Design, with manuals. E-1 F. Class Discussion Reading List F-1 G. The Configuration Aerodynamicist s Bookshelf G-1