Low Speed Wind Tunnel Testing

724 Pages·1999·57.18 MB·English

by  J. B. Barlow

LOW-SPEED WIND
TUNNEL TESTING
THIRD EDITION
-.*
1%
Jewel B. Barlow
William H. Rae, Jr.
Alan Pope
A WILEY-MTERSCIENCE PUBLICATION
JOHN WILEY & SONS, INC.
NewYork Chichester Weinheim Brisbane Singapore Toronto

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Copyright B 1999 by John Wiley & Sons. All rights reserved.
Published simultaneously in Canada.
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Librcuy of Congress Cataloging-in-Public012'onD ata:
Barlow, Jewel B.
Low speed wind tunnel testing I by Jewel B. Barlow, William H.
Rae, Alan Pope. - 3rd ed.
p. cm.
Rev. Ed. of: Low-speed wind tunnel testing / WiUiam H. Rae, Jr.,
Alan Pope. 2nd ed. ~1984.
"A Wiley-Interscience publication."
Includes bibliographical references and index.
ISBN 0-471-55774-9 (cloth : alk. paper)
1. Wind tunnels. I. Rae, William H. II. Pope, Alan, 1913-
III. Pope. Alan. 1913- Low-speed wind tunnel testing. IV. Title.
TL567.W5B285 1999
629.134'524~21 98-28891
Printed in the United States of America.
CONTENTS
Preface
1 Introduction
1.1 Aerodynamics
1.2 Properties of Air and Water
1.3 Flow Similarity
1.4 Incompressible Flow
1.5 Time Dependence of the Solutions
1.6 Aeroacoustics
References and Notes
2 Wind Tunnels
Impottant Parameters for Similarity
Research and Development Programs
Types of Wind Tunnels
Aeronautical Wind Tunnels
Smoke Tunnels
Automobile Wind Tunnels
Aeroacoustic Wind Tunnels
Water Tunnels
General-Purpose Wind Tunnels
Environmental Wind Tunnels
References and Notes
3 Wind Tunnel Design
Overall Aerodynamic Objective
Basic Decisions
Power Considerations
Section Loss Coefficients
Energy Ratios of Some Typical Circuits
Fan-Straightener Section
Return (or Second) Diffuser
Cooling
Breather: Vibrations
Test-Section Flow Quality
vi CONTENTS
3.11 Approach to Flow Improvement
3.12 Drive System
3.13 Wind Tunnel Construction
3.14 Test-Section Inserts
3.15 Safety
References and Notes-
4 Pressure, Flow, and Shear Stress Measurements
4.1 Pressure
4.2 Temperature
4.3 Flow Insbumentation
4.4 Boundary Layers and Surface Shear Stress
4.5 Flow Field and Surface Analyses
References and Notes
5 Flow Wsualiiation
5.1 Path-, Streak-, Stream-, and 'Ilmelines
5.2 Direct Visualization
5.3 Surface Flow Visualization
5.4 Flow Field Visualization
5.5 Data-Driven Visualization
References and Notes
6 Calibration of the Test Section
6.1 Test-Section Flow Calibration
6.2 Wind Tunnel Boundary Layers
6.3 Acoustics
6.4 Wind Tunnel Data Systems
References and Notes
7 Forces and Moments from Balance Measurements
7.1 Forces, Moments, and Reference Frames
7.2 Balances
7.3 Balance Requirements and Specifications
7.4 External Balances
7.5 Fundamentals of Model Installations
7.6 Internal Balances
References and Notes
8 Use of Wind Tunnel Data: Scale Effects
8.1 Boundary Layer
8.2 Trip Strip
CONTENTS vii
8.3 Drag
8.4 Lift Curve
8.5 Flap Characteristics
8.6 Pitching Moment
8.7 Longitudinal Stability and Control
8.8 Directional Stability and Control
8.9 Lateral Stability and Control
8.10 Correlation of Wind Tunnel to Flight Data
References and Notes
9 Boundary Corrections I: Basics and Two-Dimensional Cases
9.1 Descriptions of Wind Tbnnel Flow
9.2 Mathematical Models
9.3 Related Developments
9.4 Bodies Spanning the Tunnel
References and Notes
10 Boundary Corrections 11: Three-Dimensional Flow
Buoyancy
Solid Blockage
Wake Blockage
Streamline Curvature
General Downwash Corrections
Lift Distribution Interference
Downwash Corrections
Flow behind the Wing
Summary: Closed Test Section
Summary: Open Jet
References and Notes
11 Boundary Corrections III: Additional Applications
11.1 Reflection Plane Models
11.2 Swept Wings: Nonuniform Lift
11.3 Control Surface Hinge Moments
11.4 Ground Proximity Effects for Aircraft
11.5 Downwash Corrections: Powered Models
11.6 Boundary Correction: Propellers
11.7 Boundary Effects: V/STOL Experiments
References and Notes
12 Additional Considerations for Aerodynamic Experiments
12.1 Wind Tunnel Experiments
12.2 Uncertainty of Measurements
viii CONTENTS
12.3 Aspects of Design of Experiments
12.4 Model Design and Construction
12.5 Planning the Experiment
12.6 Arranging for Use of Facilities
References and Notes
13 Aircraft and Aircraft Components
13.1 General Test Procedure
13.2 Components
13.3 Complete Configurations
13.4 Power Effects of Propeller Aircraft
13.5 Power Effects of Jet Aircraft
13.6 V/STOL Vehicles
13.7 Reentry Landing Craft
References and Notes
14 Ground Vehicles
14.1 Production Automobiles
14.2 Racing Vehicles
14.3 Trucks, Motorcycles, and Other Vehicles
14.4 Systems for Ground Vehicle Experiments
References and Notes
15 Marine Vehicles
15.1 Surface Vessels: Above the Water
15.2 Surface Vessels: Below the Water
15.3 Underwater Vehicles
15.4 Sailing Vessels
References and Notes
16 Wind Engineering
16.1 Modeling the Atmospheric Surface Wind
16.2 Local Pressures and Panel Loads
16.3 Loads on Complete Structures
16.4 Structures Exhibiting Elastic Motion
References and Notes
17 Small Wind lhnnels
17.1 Tests Least Affected by Reynolds Number
17.2 The Small Wind Tunnel for Instruction
17.3 Low-Reynolds-Number Testing
References and Notes
CONTENTS ix
18 Dynamic Tests
18.1 Spin Characteristics and Spin Recovery
18.2 Dynamic Aeroelastic Experiments
18.3 Store Release or Jettison Experiments
18.4 Parabrake Evaluations
18.5 Cavity Resonance
References and Notes
Appendix 1 Subsonic Aerodynamic Testing Association (SATA)
Appendix 2 Numerical Constants and Unit Conversions
Index

PREFACE
The practice of low-speed experimental aerodynamics has continued to evolve and
continues to be a cornerstone in the development for a wide range of vehicles
and other devices that must perform their functions in the face of forces imposed
by strong flows of air or water. In the 1970s and continuing into the early 1980s a
sizable group of experts predicted that the need for aerodynamic experiments,
particularly in the subsonic regime, would rapidly disappear as computational fluid
dynamics would in a rather short time become sufficiently capable so that all
needed information would be available from computational simulations at a cost-
effectiveness superior to that of experiments. It is true that computational capability
has continued to improve at a substantial pace, but it has not come close to reaching
a level sufficient to replace the need for experimental data in development projects.
There are now no credible predictions that computational simulation will replace
the need for all data from physical experiments in any significant development
projects. Turbulence continues to confound us in many respects.
Increasing capability of computing equipment has contributed greatly to changes
in the practice of experimental aerodynamics by increasing dramatically the rate at
which measurements can be obtained, by making additional measurement methods
such as pressure-sensitive paint feasible, and by making it possible to share the
results of experiments in practically real time with people at widely separated
geographic locations. There is also a need to integrate directly the outcomes of
experiments with the outcomes of computational simulations as each progresses.
This is a capability that continues to be a work in progress at many laboratories.
Nevertheless, as stated in the preface to the previous edition, the basic methods
and theory have remained unchanged over several decades. The scope of the book
remains the same: to help students taking a course in wind tunnel experimentation
and to furnish a reference source to wind tunnel engineers and others who use wind
tunnels to solve problems of fluid flow or vehicle development. Considerable new
material has been added in this edition. Some material has been added to the
treatment of fundamental issues, including a more extensive theoretical introduction
to help relate experimental work to computational simulations and a chapter on the
design of experiments and data quality. The most obvious additions are separate
chapters on ground vehicle experiments, marine vehicle experiments, and wind
engineering, with the material on aircraft divided into two chapters. Because of the
wide scope, we continue to include material on tunnel design, calibration, and simple
as well as more sophisticated instrumentation. All the material in the book is directed
to low-speed experiments. The subject of high-speed wind tunnel testing is covered
xi