SAE R-430-2015 Aerodynamics of Road Vehicles.pdf

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1、 6584_Book.indb 1 11/24/15 5:36 PM Theory and Applications of Aerodynamics for Ground Vehicles By T. Yomi Obidi (Product Code: R-392) Fundamentals of Automobile Body Structure Design By Donald E. Malen (Product Code: R-394) ; 8777323(.y) 72777(us.); 72777;us cs.g p:/ /bks.s.g 6584_Book.indb 2 11/24/

2、15 5:36 PM sy 6584_Book.indb 3 11/24/15 5:36 PM Copyright 2016 SAE International eISBN: 978-0-7680-8253-1 : us cs.g : +8777323(s) +72777(us) Fx: +72777 Copyright 2016 SAE International. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, distributed, or

3、trans- mitted, in any form or by any means without the prior written permission of SAE International. For permission and licensing requests, contact SAE Permissions, 400 Commonwealth Drive, Warrendale, PA 15096-0001 USA; email: copyrightsae.org; phone: 724-772-4028; fax: 724-772-9765. SAE Order Numb

4、er R-430 http:/dx.doi.org/10.4271/r-430 Library of Congress Cataloging-in-Publication Data Aerodynamik des Automobils. EnglishAerodynamics of road vehicles.Fifth Edition/by Thomas Schuetz.pages cmISBN 978-0-7680-7977-7 1. Motor vehiclesAerodynamics. I. Schuetz, Thomas, 1982- editor. II. Title. TL245

5、.A4813 2015629.231-dc232015030298 Information contained in this work has been obtained by SAE International from sources believed to be reliable. However, neither SAE International nor its authors guarantee the accuracy or completeness of any information published herein and neither SAE Internationa

6、l nor its authors shall be responsible for any errors, omissions, or damages arising out of use of this informa- tion. This work is published with the understanding that SAE International and its authors are supplying information, but are not attempting to render engineering or other professional se

7、rvices. If such services are required, the assistance of an appropriate professional should be sought. ISBN-Print 978-0-7680-7977-7 ISBN-PDF 978-0-7680-8253-1 ISBN-epub 978-0-7680-8255-5 ISBN-prc 978-0-7680-8254-8 To purchase bulk quantities, please contact: SAE Customer Service Email: CustomerServi

8、cesae.org Phone: +1 877-606-7323 (inside USA and Canada) +1 724-776-4970 (outside USA) Fax: +1 724-776-0790 Visit the SAE International Bookstore at books.sae.org 6584_Book.indb 4 11/24/15 5:36 PM C xv wg .xix Cp 1 I u u .1 1.1 Scope 1 1.1.1 The Role of Aerodynamics in Vehicle Design 1 1.1.2 The Cha

9、racter of V ehicle Aerodynamics 2 1.1.3 Related Fields . 5 1.2 Historical Development of V ehicle Aerodynamics . 7 1.2.1 Literature 7 1.2.2 Ahead of Its Time . 9 1.2.3 Dominant Reference Number c D10 1.2.4 Creating Shapes for Cars . 11 1.2.5 “Borrowed” Shapes . 12 1.2.6 The “Streamline” Era . 14 1.2

10、.7 Early Investigations with Parameters . 25 1.3 From Horseless Carriage to Automobile . 26 1.3.1 Stamping 26 1.3.2 “Bathtub” Body 27 1.3.3 One-Volume Bodies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 1.4 Rear-End Shapes . 34 1.4.1 Kamm-Back . 34 1.4.2 Fastback 37 1.

11、4.3 Notchback . 38 1.4.4 Hatchback . 39 1.5 Directional Stability 39 1.6 Commercial Vehicles . 42 1.7 Motorcycles and Helmets . 46 1.8 Internal Flows . 47 1.8.1 Engine Compartment . 47 1.8.2 Passenger Compartment 48 1.9 Development Strategies . 49 1.9.1 Detail Optimization 49 1.9.2 Shape Optimizatio

12、n 53 1.9.3 Limit Strategy . 57 1.10 Design and Aerodynamics 60 1.11 Development Tools . 63 1.11.1 Wind Tunnels 63 1.11.2 Rating 65 6584_Book.indb 5 11/24/15 5:36 PM s 1.11.3 Classical Approach . 68 1.11.4 CFDIntegrated Methods . 70 Cp 2 Tp.75 2.1 Basic Equations in Fluid Dynamics . 75 2.1.1 Conserva

13、tion Laws . 75 2.1.2 Kinematics and Dynamics of Flow Fields 76 2.1.3 The Continuity Equation 81 2.1.4 The Euler Equation . 82 2.1.5 The Bernoulli Equation 83 2.1.6 Potential Theory . 84 2.1.7 The Navier-Stokes Equation . 85 2.1.8 Integral Forms of the Conservation Laws 88 2.2 Dynamics of Inviscid Fl

14、ow 93 2.2.1 Interpreting Streamline Patterns 93 2.2.2 Planar Model Flows 95 2.2.3 Vortex Flows 105 2.3 The Dynamics of the Frictional Flow 111 2.3.1 The Reynolds Number 111 2.3.2 The Prandtl Boundary Layer Concept . 112 2.3.3 Boundary Layer Separation 115 2.3.4 Boundary Layer Turbulence . 118 2.3.5

15、Drag of Simple Bodies . 123 2.3.6 Multi-Body Systems . 131 2.3.7 Pipe Systems with Internal Flow 134 2.4 Appendix 146 2.4.1 Density and Viscosity of Air 146 2.4.2 Compressibility Effects . 148 Cp 3 Cup 151 3.1 The Signicance of Aerodynamic Drag . 151 3.2 Theory of Driving Resistance . 154 3.2.1 Roll

16、ing Resistance . 154 3.2.2 Aerodynamic Drag 156 3.2.3 Grade Resistance 158 3.2.4 Acceleration 158 3.2.5 Overall Driving Resistance . 159 3.2.6 Example . 159 3.3 Performance 160 3.3.1 Acceleration and Elasticity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160 3.3.2 Ascending Ability .

17、162 3.3.3 Top Speed 163 3.4 Consumption . 165 3.4.1 Calculating Fuel Consumption 166 6584_Book.indb 6 11/24/15 5:36 PM s 3.4.2 Consumption Measurement and CO 2and Energy Equivalents 168 3.5 Driving Cycles 170 3.5.1 History 171 3.5.2 New European Driving Cycle (NEDC) . 171 3.5.3 NEDC Cycle for Hybrid

18、 Drives . 173 3.5.4 United States Cycles . 173 3.5.5 Asian Cycles 175 3.5.6 WLTPWorldwide Harmonized Light Vehicles Test Procedure 176 3.5.7 Realistic Driving Cycles 177 3.6 Possibilities for Reducing Fuel Consumption . 177 3.6.1 Energy Flow Diagram 177 3.6.2 Engine Efciency and Engine Maps 179 3.6.

19、3 Ancillary Components . 181 3.6.4 Transmission . 183 3.6.5 Vehicle Mass 185 3.6.6 Rolling Resistance . 186 3.6.7 Aerodynamic Drag 186 3.7 Reducing Aerodynamic Drag . 187 3.7.1 Possibilities for Reducing Resistance . 188 3.7.2 Weight Equivalency . 189 3.7.3 Amortization Analysis . 189 3.8 CO 2Legisl

20、ation and Labels . 191 3.8.1 EU Legislation 191 3.8.2 CO 2Labels in the EU 192 3.8.3 Legislation in the United States. . . . . . . . . . . . . . . . . . . . . . . . . . 193 3.8.4 CO 2Labels in the United States . 194 3.8.5 Legislation in Asia . 196 Cp 4 TIu g197 4.1 Aerodynamic Forces and Force Coef

21、cients . 201 4.1.1 Buckingham Theorem . 205 4.2 Flow Field Around Cars 206 4.2.1 Dead Wake . 208 4.2.2 Longitudinal Vortices 215 4.2.3 Internal Flow . 216 4.2.4 Environmental Inuences 217 4.2.5 Inuence of the Reynolds Number . 219 4.3 Analysis of Aerodynamic Drag Components 220 4.3.1 Pressure and Fr

22、iction Drag . 220 4.3.2 Microdrag 223 4.3.3 Analysis by Individual Components . 226 6584_Book.indb 7 11/24/15 5:36 PM s 4.4 Other Components of Aerodynamic Force and Aerodynamic Moment . 246 4.4.1 Lift and Pitching Moment 246 4.4.2 Side Force and Yaw Moment 248 4.4.3 Roll Moment. . . . . . . . . . .

23、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250 4.5 Inuence on Aerodynamic Forces . 250 4.5.1 The Inuence of Basic Shape 252 4.5.2 Cooling Air Effect . 320 4.5.3 Add-On Parts . 334 4.5.4 Interference . 367 4.6 The Aerodynamic Development Process . 380 4.6.1 Goal Denition . 382 4.6

24、.2 Project Milestones and Tools 383 4.6.3 Examples. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 388 4.7 Drag and Lift of Passenger Cars in Production 390 4.7.1 Overview of Competitors by Vehicle Class 390 4.7.2 Drag Surface Area c D A x. 392 4.7.3 Intercom

25、parison in Accordance with EADE . 394 4.7.4 Inuence of Vehicle Concepts . 396 4.7.5 Inuence of Equipment and Engine 400 4.7.6 Driving on the Ceiling? 402 4.8 Future Development . 403 4.9 Reference Bodies 406 4.9.1 SAE Reference Body . 406 4.9.2 Ahmed Body . 409 4.9.3 DrivAer Body . 410 Cp 5 Dg .413

26、5.1 Unsteady Aerodynamic Forces and Moments . 414 5.1.1 Overtaking Maneuvers . 414 5.1.2 Side Wind 416 5.2 Dynamic Driving Effects . 445 5.2.1 Single-Track Model 445 5.2.2 Reaction to Lift Forces . 449 5.2.3 Aerodynamic Axle Load Relief Settings 459 5.2.4 Reaction to Crosswinds 461 Cp 6 u C 473 6.1

27、Component Loads . 474 6.1.1 Component Loads and Pinpointing Them 474 6.1.2 Doors, Flaps, and Outside Mirrors . 476 6.1.3 Windshield Wipers 480 6.2 Comfort When Driving with the Top Down . 487 6.2.1 Objective . 487 6584_Book.indb 8 11/24/15 5:36 PM s 6.2.2 Airow with Convertible Top Open . 488 6.2.3

28、Wind Noise . 489 6.2.4 Thermal Comfort 489 6.2.5 Design Solutions for Convertibles . 496 6.2.6 Design Solutions for Sunroofs . 501 6.3 Prevention of Vehicle Soiling . 503 6.3.1 Basics of Vehicle Soiling 503 6.3.2 External Contamination 508 6.3.3 Vehicle-Induced Contamination . 523 Cp 7 CgI w. 527 7.

29、1 Cooling Requirements . 527 7.1.1 Representative Operating Conditions 528 7.1.2 Components and Systems 529 7.1.3 Other Requirements . 531 7.2 Cooling System . 532 7.2.1 Engine Cooling System Circuit 532 7.2.2 Fundamentals of Heat Transfer 533 7.2.3 Design of Heat Exchanger 535 7.2.4 Heat Exchangers

30、 in the Vehicle 537 7.3 Internal Flow . 541 7.3.1 Operating Conditions 541 7.3.2 Cooling Module . 544 7.3.3 Fan 545 7.4 Optimizing the Overall System . 547 7.4.1 Calculation of the Cooling Air Mass Flow 548 7.4.2 Inuence Parameters of the Internal Flow 551 7.4.3 Air Intakes and Cooling Air Ducts . 5

31、53 7.4.4 Cooling Matrix 554 7.4.5 Fan 559 7.4.6 Engine Compartment 561 7.4.7 Cooling Air Outlets 562 7.5 Measurement Technology for Cooling Airow 563 7.5.1 Vane Anemometers 564 7.5.2 Pressure Measurements 564 7.5.3 Optical Measuring Methods 565 7.5.4 Hot-Wire Anemometry . 566 Cp 8 u . 569 8.1 The In

32、uence of Airow on the Interior and Exterior Noise of Motor Vehicles 569 8.2 Aerodynamic Noise Generation . 573 8.3 Aeroacoustic Measuring Systems 574 8.3.1 Aeroacoustic Wind Tunnels . 574 6584_Book.indb 9 11/24/15 5:36 PM s 8.3.2 Measuring Interior Noise . 576 8.3.3 Measuring Exterior Noise 576 8.3.

33、4 Measuring Structure-Borne Sound . 581 8.3.5 Sound Source Location with Special Instruments 582 8.4 Main Noise Sources and Options for Their Reduction 583 8.4.1 Leaks 583 8.4.2 Rear View Mirrors . 584 8.4.3 Windshield Wipers 586 8.4.4 Antennas . 586 8.4.5 A-Pillar 587 8.4.6 Cavity Resonances 589 8.

34、4.7 Sun Roof Opening Noise . 591 8.4.8 Wheel Housings 591 8.4.9 Underbody . 592 8.4.10 Reduction of Interior Noise by Using Special Acoustic Glass Windows . 593 8.4.11 Convertibles 593 8.5 Psycho-Acoustic Aspects . 594 8.5.1 Assessing Different Behavior Under Yaw Conditions . 596 8.5.2 Simulation wi

35、th Static Vortex Generators . 597 8.5.3 Simulation with Dynamic Vortex Generators 597 8.5.4 Noise Synthesis . 597 Cp 9 Hg-. 601 9.1 Introduction 601 9.1.1 Denition 601 9.1.2 Preview 602 9.2 Outline of the History . 602 9.2.1 Racing Cars 602 9.2.2 Record-Breaking Vehicles . 609 9.2.3 Sports Cars . 61

36、8 9.3 Vehicle Classes 623 9.4 Race Tracks . 629 9.5 Regulations 631 9.6 Aerodynamics, Performance, and Handling Characteristics . 635 9.6.1 Drag . 635 9.6.2 Downforce . 639 9.6.3 Balance 643 9.6.4 Road Performance . 649 9.6.5 Efciency 651 9.6.6 Cooling and Ventilation 654 9.6.7 Oblique Incident Flow

37、 . 656 9.6.8 Slipstream 659 6584_Book.indb 10 11/24/15 5:36 PM s 9.7 Aerodynamics of Components 661 9.7.1 Basic Body . 662 9.7.2 Wings 666 9.7.3 Spoiler and Gurneys . 677 9.7.4 Ground Effect . 682 9.7.5 Diffusers . 686 9.7.6 Inlets and Outlets . 696 9.7.7 Air Guiding Elements (Vanes) . 703 9.7.8 Whe

38、els . 707 Cp 10 C . 711 10.1 Target Group 711 10.2 Driving Resistances and Fuel Consumption. . . . . . . . . . . . . . . . . . . . . . . 713 10.3 History of Commercial V ehicle Aerodynamics 718 10.4 Principles of Commercial V ehicle Aerodynamics 721 10.4.1 Straight/Oblique Flow . 723 10.4.2 Legislat

39、ive Framework . 727 10.5 Tools for Optimizing Commercial Vehicle Aerodynamics 728 10.5.1 Challenges Posed by Commercial Vehicles 728 10.5.2 Model-Scale Wind Tunnel 728 10.5.3 Full-Scale Wind Tunnel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 732 10.5.4 CFD Simulation . 735 10.5.

40、5 Test Drives with Wheel Hub Measurement Device . 736 10.6 Optimizing Aerodynamic Drag on Trucks 739 10.6.1 Characteristic Airow and Pressure Conditions . 739 10.6.2 Cab 741 10.6.3 Mirrors and Attachments on the Cab . 748 10.6.4 Airow Through the Engine Compartment . 751 10.6.5 Chassis 754 10.6.6 Se

41、mitrailers and Bodies 758 10.6.7 Concept Vehicles 769 10.7 Optimizing Aerodynamic Drag on Buses and Coaches . 772 10.7.1 Characteristic Airow and Pressure Conditions . 772 10.7.2 Front 773 10.7.3 Rear View Mirrors . 775 10.7.4 Windscreen Wipers 777 10.7.5 Underbody . 778 10.7.6 Wheels and Wheel Cove

42、rs 778 10.7.7 Airow Through the Engine Compartment . 780 10.7.8 Rear . 781 10.8 Aerodynamic Interaction . 782 10.8.1 Nose-to-Tail Driving . 782 10.8.2 Tipping and Susceptibility to Side Winds . 784 10.8.3 Aerodynamic Loads on Components . 786 6584_Book.indb 11 11/24/15 5:36 PM s 10.8.4 Dust Turbulen

43、ce 786 10.8.5 Intake of Warm Air 787 10.8.6 Management of Exhaust Gas 788 10.9 Vehicle Soiling 789 10.9.1 Task Description and Testing Methods . 789 10.9.2 Foreign Soiling 791 10.9.3 Self-Soiling . 792 Cp 11 M . 795 11.1 Introduction 795 11.2 Historical Review and Current Types 796 11.2.1 History of

44、 Motorcycle Aerodynamics 796 11.2.2 Current Motorcycle Categories 801 11.2.3 Special Bikes 807 11.3 Aerodynamic Tasks 811 11.3.1 Aerodynamic Forces and Moments . 811 11.3.2 Aerodynamics and Longitudinal Dynamics . 813 11.3.3 Aerodynamics and Lateral Dynamics 821 11.3.4 Cooling and Internal Flow 831

45、11.3.5 Wind and Weather Protection . 835 11.3.6 Aeroacoustics . 837 11.4 Development Methods . 838 11.4.1 Development Process 838 11.4.2 Simulation (CFD) 839 11.4.3 Wind Tunnel 853 11.4.4 Road Test 864 11.4.5 OutlookThe Future of Development Methods . 868 11.5 Aerodynamic DesignPractical Examples .

46、869 11.5.1 Measures to Optimize Drag and Lift . 869 11.5.2 Design of Internal Flows, Cooling, and Heat Protection . 872 11.5.3 Measures for Wind and Weather Protection . 875 11.6 Outlook 876 Cp 12 H 877 12.1 Head Protection Technology 877 12.2 Motorcycle Helmets . 879 12.2.1 Aerodynamics 879 12.2.2 Aeroacoustics . 887 12.2.3 Ventilation and Rain Tests 896 12.3 Helmets for Open Race Cars 901 12.3.1 History 901 12.3.2 Aerodynamics and Venti