COMPUTATIONAL FLUID DYNAMICS The Basics with Applications

COMPUTATIONAL FLUID DYNAMICS The Basics with Applications John D. Anderson, Jr. Department of Aerospace Engineering University of Maryland McGraw-H...
Author: Julian Gordon
3 downloads 2 Views 245KB Size
COMPUTATIONAL FLUID DYNAMICS

The Basics with Applications

John D. Anderson, Jr. Department of Aerospace Engineering University of Maryland

McGraw-Hill, Inc. New York St. Louis San Francisco Auckland Bogota Caracas Lisbon London Madrid Mexico City Milan Montreal New Delhi San Juan Singapore Sydney Tokyo Toronto

CONTENTS

Part I 1

Preface Basic Thoughts and Equations Philosophy of Computational Fluid Dynamics 1.1 1.2 1.3 1.4

1.5 1.6

2

Computational Fluid Dynamics : Why? Computational Fluid Dynamics as a Research Tool Computational Fluid Dynamics as a Design Tool The Impact of Computational Fluid Dynamics-Some Other Examples 1.4 .1 Automobile and Engine Applications 1.4 .2 Industrial Manufacturing Applications 1 .4 .3 Civil Engineering Applications 1 .4.4 Environmental Engineering Applications 1 .4.5 Naval Architecture Applications (Submarine Example) Computational Fluid Dynamics: What Is It? The Purpose of This Book

The Governing Equations of Fluid Dynamics: Their Derivation, a Discussion of Their Physical Meaning, and a Presentation of Forms Particularly Suitable to CFD 2.1 2.2

2.3 2.4

Introduction Models of the Flow 2.2 .1 Finite Control Volume 2.2 .2 Infinitesimal Fluid Element 2.2 .3 Some Comments The Substantial Derivative (Time Rate of Change Following a Moving Fluid Element The Divergence of the Velocity : Its Physical Meaning 2 .4 .1 A Comment

3 4 6 9 13 14 17 19 20 22 23 32

37 38 40 41 42 42 43 47 48

XU

CONTENTS

2.5

The Continuity Equation 2.5 .1 Model of the Finite Control Volume Fixed in Space 2.5 .2 Model of the Finite Control Volume Moving with the Fluid 2.5 .3 Model of an Infinitesimally Small Element Fixed in Space 2.5 .4 Model of an Infinitesimally Small Fluid Element Moving with the Flow 2.5 .5 All the Equations Are One: Some Manipulations 2.5 .6 Integral versus Differential Form of the Equations : An Important Comment 2.6 The Momentum Equation 2.7 The Energy Equation 2.8 Summary of the Governing Equations for Fluid Dynamics: With Comments 2.8 .1 Equations for Viscous Flow (the Navier-Stokes Equations) 2.8 .2 Equations for Inviscid Flow (the Euler Equations) 2.8 .3 Comments on the Governing Equations 2.9 Physical Boundary Conditions 2.10 Forms of the Governing Equations Particularly Suited for CFD : Comments on the Conservation Form, Shock Fitting, and Shock Capturing 2.11 Summary Problems

3

Mathematical Behavior of Partial Differential Equations: The Impact on CFD 3.1 3.2 3.3

Introduction Classification of Quasi-Linear Partial Differential Equations A General Method of Determining the Classification of Partial Differential Equations: The Eigenvalue Method 3.4 General Behavior of the Different Classes of Partial Differential Equations: Impact on Physical and Computational Fluid Dynamics 3.4.1 Hyperbolic Equations 3 .4 .2 Parabolic Equations 3.4 .3 Elliptic Equations 3.4 .4 Some Comments : The Supersonic Blunt Body Problem Revisited 3.5 Well-Posed Problems 3 .6 Summary Problems

Part II 4

49 49 51 53 55 56 60 60 66 75 75 77 78 80 82 92 93 95 95 97 102 105 106 111 117 119 120 121 121

Basics of the Numerics Basic Aspects of Discretization 4.1 4 .2

Introduction Introduction to Finite Differences

125 125 128

CONTENTS

4.3 4.4 4.5 4.6

Difference Equations Explicit and Implicit Approaches : Definitions and Contrasts Errors and an Analysis of Stability 4.5 .1 Stability Analysis : A Broader Perspective Summary

GUIDEPOST Problems

5 Grids with Appropriate Transformations 5.1 5.2 5.2 5.4 5.5 5.6 5.7

Introduction General Transformation of the Equations Metrics and Jacobians Form of the Governing Equations Particularly Suited for CFD Revisited: The Transformed Version A Comment Stretched (Compressed) Grids Boundary-Fitted Coordinate Systems; Elliptic Grid Generation

GUIDEPOST 5.8 Adaptive Grids 5.9 Some Modern Developments in Grid Generation 5.10 Some Modern Developments in Finite-Volume Mesh Generation: Unstructured Meshes and a Return to Cartesian Meshes 5.11 Summary Problems

6 Some Simple CFD Techniques : A Beginning 6.1 6.2 6.3

Introduction The Lax-Wendroff Technique MacCormack's Technique

GUIDEPOST 6.4

6.5 6.6 6.7 6 .8

Some Comments : Viscous Flows, Conservation Form, and Space Marching 6.4.1 Viscous Flows 6.4.2 Conservation Form 6.4.3 Space Marching The Relaxation Technique and Its Use with Low-Speed Inviscid Flow Aspects of Numerical Dissipation and Dispersion; Artificial Viscosity The Alternating-Direction-Implicit (ADI) Technique The Pressure Correction Technique: Application to Incompressible Viscous Flow 6.8.1 Some Comments on the Incompressible Navier-Stokes Equations

%IIl

142 145 153 165 165 166 167 168 168 171 178 183 186 186 192 193 200 208 210 212 215 216 216 217 222 223 225 225 225 226 229 232 243 247 248

XIv

CONTENTS

6.8 .2 6.8 .3 6.8 .4 6.8 .5 6.8 .6

Some Comments on Central Differencing of the Incompressible Navier-Stokes Equations; The Need for a Staggered Grid The Philosophy of the Pressure Correction Method The Pressure Correction Formula The Numerical Procedure: The SEMPLE Algorithm Boundary Conditions for the Pressure Correction Method

GUIDEPOST 6.9

Some Computer Graphic Techniques Used in CFD 6.9 .1 xy Plots 6.9 .2 Contour Plots 6.9 .3 Vector and Streamline Plots 6.9 .4 Scatter Plots 6.9 .5 Mesh Plots 6.9 .6 Composite Plots 6.9 .7 Summary on Computer Graphics 6.10 Summary Problems

Part III

250 253 254 261 262 264 264 264 265 270 273 273 274 274 277 278

Some Applications

7 Numerical Solutions of Quasi-One-Dimensional Nozzle Flows 7.1 7.2

Introduction: The Format for Chapters in Part III Introduction to the Physical Problem: Subsonic-Supersonic Insentropic Flow 7.3 CFD Solution of Subsonic-Supersonic Isentropic Nozzle Flow: MacCormack's Technique 7.3 .1 The Setup 7.3 .2 Intermediate Results: The First Few Steps 7.3 .3 Final Numerical Results: The Steady-State Solution 7.4 CFD Solution of Purely Subsonic Isentropic Nozzle Flow 7.4.1 The Setup: Boundary and Initial Conditions 7.4.2 Final Numerical Results: MacCormack's Technique 7.4 .3 The Anatomy of a Failed Solution 7.5 The Subsonic-Supersonic Isentropic Nozzle Solution Revisited : The Use of the Governing Equations in Conservation Form 7.5 .1 The Basic Equations in Conservation Form 7.5 .2 The Setup 7.5 .3 Intermediate Calculations : The First Time Step 7.5 .4 Final Numerical Results: The Steady State Solution

283 283 285 288

288 308 313 325 327 330 325 336 337 340 345 351

CONTENTS

7.6

7.7

A Case with Shock Capturing 7.6.1 The Setup 7.6.2 The Intermediate Time-Marching Procedure: The Need for Artificial Viscosity 7.6.3 Numerical Results Summary

8 Numerical Solution of a Two-Dimensional Supersonic Flow: Prandtl-Meyer Expansion Wave 8.1 8.2 8.3

8.4

Introduction Introduction to the Physical Problem: Prandtl-Meyer Expansion Wave-Exact Analytical Solution The Numerical Solution of a Prandtl-Meyer Expansion Wave Flow Field 8.3 .1 The Governing Equations 8 .3 .2 The Setup 8.3 .3 Intermediate Results 8.3 .4 Final Results Summary

9 Incompressible Couette Flow: Numerical Solutions by Means of an Implicit Method and the Pressure Correction Method 9.1 9.2 9.3

9.4 9.5

10

Introduction The Physical Problem and Its Exact Analytical Solution The Numerical Approach : Implicit Crank-Nicholson Technique 9.3 .1 The Numerical Formulation 9.3 .2 The Setup 9.3 .3 Intermediate Results 9.3 .4 Final Results Another Numerical Approach: The Pressure Correction Method 9.4 .1 The Setup 9.4 .2 Results Summary Problem

Supersonic Flow over a Flat Plate: Numerical Solution by Solving the Complete Navier-Stokes Equations 10 .1 - Introduction 10.2 The Physical Problem 10 .3 The Numerical Approach : Explicit Finite-Difference Solution of the Two-Dimensional Complete Navier-Stokes Equations 10 .3 .1 The Governing Flow Equations 10 .3 .2 The Setup

xv 356 358 363 364 372

374 374 376 377 377 386 397 407 414

416 416 417 420 421 425 426 430 435 436 442 445 446

447 447 449 450 450 452

%Vi

CONTENTS

10 .4

10 .5 10.6

Part IV 11

10 .3 .3 The Finite-Difference Equations 10 .3 .4 Calculation of Step Sizes in Space and Time 10 .3 .5 Initial and Boundary Conditions Organization of Your Navier-Stokes Code 10.4 .1 Overview 10.4 .2 The Main Program 10.4 .3 The MacCormack Subroutine 10.4.4 Final Remarks Final Numerical Results: The Steady State-Solution Summary

Other Topics Some Advanced Topics in Modern CFD : A Discussion 11 .1 11 .2

Introduction The Conservation Form of the Governing Flow Equations Revisited: The Jacobians of the System 11 .2 .1 Specialization to One-Dimensional Flow 11 .2 .2 Interim Summary 11 .3 Additional Considerations for Implicit Methods 11 .3 .1 Linearization of the Equations: The Beam and Warming Method 11 .3 .2 The Multidimensional Problem: Approximate Factorization 11 .3 .3 Block Tridiagonal Matrices 11 .3 .4 Interim Summary 11 .4 Upwind Schemes 11 .4 .1 Flux-Vector Splitting 11 .4.2 The Godunov Approach 11 .4.3 General Comment 11 .5 Second-Order Upwind Schemes 11 .6 High-Resolution Schemes: TVD and Flux Limiters 11 .7 Some Results 11 .8 Multigrid Method 11 .9 Summary Problems

12

453 455 457 459 459 461 463 466 466 474

The Future of CFD 12 .1 12.2 12.3 12 .4 12 .5

The Importance of CFD Revisited Computer Graphics in CFD The Future of CID: Enhancing the Design Process The Future of CFD: Enhancing Understanding Conclusion

479 479 480 482 489 489 490 492 496 497 497 500 502 507 507 509 510 513 514 514 515 515 516 517 526 533

CONTENTS

Appendix A Thomas' Algorithm for the Solution of a Tridiagonal System of Equations References

XVII

534 539

Suggest Documents