Numerical and Physical Aspects of Aerodynamic Flows IV

414 Pages·1990·15.32 MB·English

by  J. H. Whitelaw (auth.)

Proceedings of a
Symposium on
Numerical and
Physical Aspects of
Aerodynamic Flows
Numerical and
Physical Aspects of
Aerodynamic Flows IV
Edited byTuncer Cebeci
With 291 Figures
Springer-Verlag Berlin Heidelberg GmbH
Dr. Tuncer Cebeci
Aerospace Engineering Department
California State University, Long Beach
Long Beach, CA 90840, USA
and
Strategic Business & Technology Development
Douglas Aircraft Company
Long Beach, CA 90846, USA
ISBN 978-3-662-02645-8
Library of Congress Cataloging-in-Publication Data
Numerica! and physical aspects ofa erodynamic tlows IV 1 edited by Tuncer Ce beci. p. cm. Based on the
fourth Symposium on Numerica] and Physical Aspects of Aerodynamic Flows, held 1116-19/89 at
California State University, Long Beach. lncludes bibliographical references.
ISBN 978-3-662-02645-8 ISBN 978-3-662-02643-4 (eBook)
DOI 10.1007/978-3-662-02643-4
!. Aerodynamics-Congresses. 1. Cebeci, Tuncer. II. Symposium on Numericaland Physical Aspects of
Aerodynamic Flows (4th: 1989: California State University)
TL570.N844 1990 629.132'3-dc20 90-9588
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Preface
This volume contains a selection of the papers presented at the Fourth Symposium
on Numerical and Physical Aspects of Aerodynamic Flows, which was held at the
California State University, Long Beach, from 16-19 January 1989. It includes
the Stewartson Memorial Lecture of Professor J.H. Whitelaw, and is divided into
three parts. The first is a collection of papers that describe the status of current
technology in two- and three-dimensional steady flows, the second deals with
two- and three-dimensional unsteady flows, and the papers in the third address
stability and transition. Each of the three parts begins with an overview of current
research, as described in the following chapters. The individual papers are edited
versions of the selected papers originally submitted to the symposium.
Four years have passed since the Third Symposium, and certain trends be
come clear if one compares the papers contained in this volume with those of
previous volumes. There are more three- than two-dimensional problems consid
ered in Part 1 and the latter address more difficult problems than in the past, for
example, the extension to higher angles of attack, to transonic flow, to leading
edge ice accretion, and to thick hydrofoils. The large number of papers in the first
part reflects the emphasis of current research and development and the needs of
industry. The emphasis in numerical methodology continues to be on interactive
methods, with solutions of Navier-Stokes equations confined to establishments
with extensive access to large computers, and on closer linkage between solution
methods for various reduced forms of the Navier-Stokes equations. For exam
ple, interactive methods are used to provide initial conditions for Navier-Stokes
solvers in the regions of flow where diffusion is important in more than one
direction. One hopes that we will soon see the development of numerical meth
ods to solve the complete time-dependent form of the equations containing all
important terms.
The subject of turbulence models is conspicious by its absence in the papers
of the Symposium, even though time-averaged equations are solved. This reflects
in part the need for greater emphasis on accuracy of numerical-solution methods,
and also reflects the status of current models. The Stewartson Memorial Lecture
reminded us that there has been little development in turbulence models since
the 1976 paper of Launder, Reece and Rodi presented solutions of equations
for the Reynolds stresses. Minor changes have been proposed to two-equation
models and algebraic-stress models have been raised and naturally declined.
The Reynolds-stress approach has yet to find widespread use, partly because of
v
the apparent increased cost of its use. We still find ourselves, as a consequence,
unable to definitely attribute differences between calculated and measured results
to one or another source, and physical experiments have either not contributed to
this process or have been ignored. Perhaps the solution to this impasse, at least in
the medium term, is to determine from physical and numerical experiments the
relative importance of terms in the mean momentum equation and to ensure that
all are represented according to this finding. Since the viscous layer represents a
perturbation to the inviscid flow for the calculation of lift, further work may only
be required where skin-friction drag is important and here again only in local
regions of flow. We may need to develop our numerical techniques to select from
available turbulence models as well as from forms of the equations.
It may be expected that direct-simulation methods, that is, those which solve
time-dependent forms of the Navier-Stokes equations to encompass the full spec
trum of turbulence energy, will gain ground to the extent that they can assist in
the design process. This is unlikely to occur in the short or medium term except
in so far as errors associated with the assumptions inherent in turbulence models
are made clear. Large computer run times are required to solve equations for
simple geometric configurations; for modest Reynolds numbers this will ensure
that, for the foreseeable future, the cost of analyzing such configurations will
remain high and, in many cases, prohibitive.
The traditional approach to experiments remains alive and well, though, in
Part 1, there are fewer papers on experiment than on calculation. It is unquestion
ably healthy to see the fruits of research directed towards the understanding of
physical processes and it is to be hoped that this type of experimental work will
regain much of the prominence that has been lost in a sea of calculations. More
direct assistance is being provided for the development of calculation methods.
As Professor Whitelaw emphasized, we must not ignore these recent findings and
attempt solutions to equations which might otherwise present greater difficulties.
A reassuring aspect of the papers of Part 1 is that some authors are clearly
seeking to live within limitations which are known and to use their methodology
to solve problems which require answers. We live in a real world and obstacles
have to be overcome, even with imperfect tools.
The state-of-the-art of unsteady flows has also advanced with current em
phasis on compressible flow and high angles of attack. The topic of dynamic
stall remains important, though its context has shifted somewhat from helicopter
rotors to maneuverability of fixed-wing aircraft. The contributions of Parts 2
and 3 fail to conceal the absence of recent activity to study the behavior of
the location of the onset of transition in unsteady flows and its influence on
dynamic stall. They do, however, reveal a better balance between calculations
and experiments, again with some of the latter directed more at advancing our
understanding of physical processes than at providing databases. It is evident,
however, that the measurement techniques are mostly traditional in nature with
little use of the modern optical-diagnostic methods about which so much has
been written. Surface-measurement techniques are still called upon to provide
VI
evidence of local flow properties which can, in principle, be measured directly.
It is satisfying to witness again the trend towards more complicated flows such
as those involving laminar-flow control and hypersonic speeds. The stability ap
proach to the prediction of the onset of turbulence continues to gain ground and
the remarkable successes which have been achieved with ~wo-dimensional mean
flows are beginning to be measured in three-dimensional work.
The four years between the Third and Fourth Symposium have seen con
siderable advancement in the field, but the progress has been more difficult and
these difficulties are likely to increase. It may be appropriate that more than
four years will pass before the next Symposium is held. On the other hand, new
developments and new requirements may justify an earlier Symposium with a
different emphasis. Time will tell.
It is a pleasure to acknowledge the contributions of all those who contributed
to the success of the Fourth Symposium and to this volume. Financial sup
port for the Symposium was provided by the Office of Naval Research, NASA
Langley and Ames Research Centers, and the Army Research Office. The as
sistance rendered by the California State University, Long Beach, was essential,
and Springer-Verlag have been of great help in the preparation of this volume. I
owe a great debt of gratitude to the authors, session chairmen, participants and
colleagues at the University and at the Douglas Aircraft Company, and an equal
dept to the authors of the papers of this volume, including those who prepared
special overviews, who responded expeditiously to my requests. The editing
process benefitted significantly from the efforts of Laju Tejwani, Sue Schimke,
Nancy Barela, Nafiz Alemdaroglu and Richard Williams, and it is a pleasure to
acknowledge their help.
Palm Springs Tuncer Cebeci
September 1989
VII
Contents
Stewartson Memorial Lecture: Experiments are Telling You
Something. J.H. Whitelaw (With 6 Figures) ......... ........ . .
Part 1. Two- and Three-Dimensional Steady Flows
Overview. BR. Williams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
1. Predictions of Airfoil Aerodynamic Performance Degradation
Due to Icing
R.J. Shaw, M.G. Potapczuk, C.S. Bidwell (With 18 Figures) 19
2. VISTRAFS: A Simulation Method for Strongly Interacting Viscous
Transonic Flow
A.E.P. Veldman, J.P.F. Lindhout, E. deBoer, M.A.M. Somers
(With 7 Figures) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
3. Coupling Procedures for Viscous-Inviscid Interaction for Attached
and Separated Flows on Swept and Tapered Wings
B.R. Williams, PD. Smith (With 5 Figures) . . . . . . . . . . . . . . . . . . . 53
4. New Possibilities of Viscous-lnviscid Numerical Techniques
for Solving Viscous Flow Equations with Massive Separation
J.C. LeBalleur (With 13 Figures) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
5. Prediction of Post-Stall Flows on Airfoils
T. Cebeci, J. Jau, D. Vitiello, K.C. Chang (With 13 Figures) 97
6. Turbulence Characteristics of Trailing-Edge Flows
on Thick and Thin Hydrofoils
T.T. Huang, L.P. Purtell, Y.T. Lee (With 12 Figures) 111
7. Computational Fluid Dynamics at NASA Ames Research Center
P. Kutler (With 10 Figures) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
8. 3-D Composite Velocity Solutions for Subsonic{fransonic Flows
R.E. Gordnier, S.G. Rubin (With 8 Figures) . . . . . . . . . . . . . . . . . . . 141
9. Calculation of Transonic Flows for Novel Engine-Airframe
Installations. A. Shmilovich, ND. Halsey (With 5 Figures) 163
10. Calculation of Three-Dimensional Boundary Layers Including
Hypersonic Flows. B. Aupoix, S. Bonnet, C. Gleyzes, J. Cousteix
(With 14 Figures) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175
IX
11. Supersonic/Hypersonic Euler Flowfield Prediction Method
for Aircraft Configurations
A. Verhoff, D.C. Stookesberry, B.M. Hopping, T R. Michal
(With 16 Figures) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189
12. Numerical Simulation of Separated and Vortical Flows on Bodies
at Large Angles of Attack. LB. Schiff, D. Degani, R.M. Cummings
(With 16 Figures) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205
Part 2. Two- and Three-Dimensional Unsteady Flows
Overview. J.D. Lang . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225
13. The Relevance of Unsteady Aerodynamics for Highly Maneuverable
and Agile Aircraft. H.E. Helin (With 7 Figures) . . . . . . . . . . . . . . . . 229
14. Experimental and Computational Studies of Dynamic Stall
L.W. Carr, M.F. Platzer, M.S. Chandrasekhara, J. Ekaterinaris
(With 13 Figures) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239
15. A Critique of the Experimental Aerodynamic Data Base for an
Oscillating Straked Wing at High Angles
A.M. Cunningham, Jr. (With 6 Figures) . . . . . . . . . . . . . . . . . . . . . . 257
16. On the Effects of Wind Tunnel Turbulence on Steady and Unsteady
Airfoil Characteristics. A.M. Wo, E.E. Covert (With 14 Figures) 269
Part 3. Stability and Transition
Overview. T. Cebeci 283
17. Applications and Suggested Directions of Transition Research
D.M. Bushnell (With 16 Figures) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287
18. Prediction of Transition on Airfoils with Separation Bubbles,
Swept Wings, and Bodies of Revolution at Incidence
T. Cebeci, H.H. Chen (With 12 Figures) . . . . . . . . . . . . . . . . . . . . . . 303
19. Transition in Hypersonic Boundary Layers
M.R. Malik (With 6 Figures) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 321
20. Transition Phenomena on Airfoils Operating at Low Chord
Reynolds Numbers in Steady and Unsteady Flow
M. Brendel, T.J. Mueller (With 10 Figures) . . . . . . . . . . . . . . . . . . . 333
21. Disturbance Growth in an Unstable Three-Dimensional
Boundary Layer. H. Bippes, B. Muller (With 14 Figures) 345
22. Experiments in Swept-Wing Transition
W.S. Saric, J.R. Dagenhart, M.C. Mousseux (With 11 Figures) 359
23. Experimental Transition and Boundary-Layer Stability Analysis
for a Slotted Swept Laminar Flow Control Airfoil
W.D. Harvey, C.D. Harris, C.W. Brooks, Jr. (With 16 Figures) 373
X
24. Leading-Edge Contamination and Relaminarization on a Swept Wing
at Incidence. D. Arnal, J.C. Juillen (With 12 Figures) . . . . . . . . . . . 391
References 403
Index of Contributors 417
XI