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•

Lecture Notes in Engineering Edited by C. A. Brebbia and S. A. Orszag

54

T. J. Mueller (Editor)

Low Reynolds Number Aerodynamics Proceedings of the Conference Notre Dame, Indiana, USA, 5-7 June 1989

Springer-Verlag Berlin Heidelberg New York London Paris Tokyo Hong Kong

Series Editors C. A. Brebbia . S. A. Orszag

Consulting Editors J. Argyris . K.-J. Bathe· A. S. Cakmak . J. Connor' R. McCrory C. S. Desai· K.-P. Holz . F. A. Leckie· G. Pinder· A. R. S. Pont J. H. Seinfeld . P. Silvester· P. Spanos' W. Wunderlich· S. Yip

Editor Thomas J. Mueller Dept. of Aerospace and Mechanical Engineering University of Notre Dame Notre Dame, IN 46556 USA

ISBN-13: 978-3-540-51884-6 001: 10.1007/978-3-642-84010-4

e-ISBN-13: 978-3-642-84010-4

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2161/3020-543210 Printed on acid-free paper.

PREFACE

Continuing interest in a wide variety of low Reynolds number applications has focused

attention on the design and evaluation of airfoil sections at chord Reynolds numbers below

500,000. These applications include remotely or robotically piloted vehicles at high altitudcs

as well as ultra-light and human powered vehicles and mini-RPVs at low altitudes. Other

examples include small axial-flow fans used to cool electronic equipment in the unpressurized

sections of high-altitude aircraft and gas turbine blades.

High Reynolds number airfoil design strategies attempt to control the onset and

development of turbulent boundary layers. This is difficult at low Reynolds numbers because

of the increased stability of attached laminar boundary layers. Therefore, laminar separation is

common even at small angles of attack at low Reynolds numbers. Under these conditions, the

development of a turbulent boundary layer usually depends on the foonation of a transitional

separation bubble.

This volume is the collection of papers presented at the Conference on Low Reynolds

Number Aerodynamics held June 4-7, 1989 at the University of Notre Dame. The Conference

was sponsored by the Department of Aerospace and Mechanical Engineering and the College of

Engineering at Notre Dame. Over fifty active researchers in this field from Europe, Canada,

and the United States were present. This Conference followed the 1986 International

Conference in London by about three years and the first Notre Dame Conference of 1985 by

four years. It is clear from the papers in this volume that a great deal of progress has been

made in understanding the occurrence and behavior of laminar separation and transition as well

as their overall effect on the performance of airfoils at low chord Reynolds numbers. The

ultimate goals of this understanding arc improved analytical methods for the design and

evaluation of a variety of practical applications. Significant progress has been made in the

achicvcmcnt of these goals.

I would like to thank the participants for their contributions and the staff of Springer­

Verlag for putting together this volume.

Thomas 1. Mueller Notre Dame, IN

July 1989

CONTENTS

XFOIL: An Analysis and Design System for Low Reynolds Number Airfoils 1 M.Drela

Prediction of Aerodynamic Performance of Airfoils in Low Reynolds Number Flows 13 D.P. Coiro and C. deNicola

A Fast Method for Computation of Airfoil Characteristics 24 A. Bertelrud

Low Reynolds Number Airfoil Design and Wind Tunnel Testing 39 at Princeton University

J.F. Donovan and M.S. Selig

Study of Low-Reynolds Number Separated Flow Past the 58 Wortmann FX 63-137 Airfoil

K.N. Ghia, G. Osswald and U. Ghia

An Interactive Boundary-Layer Stability-Transition Approach for Low-Reynolds 70 Number Airfoils

T. Cebeci and M. Mcllvaine

The Instability of Two-Dimensional Laminar Separation 82 LL. Pauley, P. Main and W.C. Reynolds

Bursting in Separating Flow and in Transition 93 F.T. Smith

A Review of Low Reynolds Number Aerodynamic Research at 104 The University of Glasgow

RA. MCD. Galbraith and FN. Caton

Experimental Aerodynamic Characteristics of the Airfoils LA 5055 115 and DU 86-084/18 at Low Reynolds Numbers

L.M.M. Boermans, FJ. Danker Duyvis, J.L. van Ingen and W.A. Timmer

Performance Measurements of an Airfoil at Low Reynolds Numbers 131 R.J. McGhee and B.S. Walker

Correlation of Theory to Wind-Tunnel Data at Reynolds Numbers Below 500,000 146 R. Evangelista, R.J. McGhee and B.S. Walker

An Experimental Study of Low-Speed Single-Surface Airfoils 161 with Faired Leading Edges

J.D. DeLaurier

A Computationally Efficient Modelling of Laminar Separation Bubbles 174 P. Dini and M.D. Maugluner

A Comparison Between Boundary Layer Measurements in a Laminar Separation 189 Bubble Flow and Linear Stability Theory Calculations

P. LeBlanc, R. Blackwelder and R. Liebeck

v

Unsteady Aerodynamics of Wortmann FX63-137 Airfoil at Low Reynolds Numbers 206 A.M. Wo and E.E. Covert

A Method to Detennine the Perfonnance of Low-Reynolds-Number Airfoils Under 218 Off-Design Unsteady Freestream Conditions

H.L. Reed and B.A. Toppe!

An Unsteady Model of Animal Hovering 231 P. Freymuth

Control of Low-Reynolds-Number Airfoils: A Review 246 M. Gad-eL-Hak

The Low Frequency Oscillation in the Flow Over a NACA 0012 Airfoil 271 with an "Iced" Leading Edge

KB.M.Q. Zaman and M.G. Potapezuk

Detachment of Turbulent Boundary Layers with Varying Free-Stream 283 Turbulence and Lower Reynolds Numbers

J.L. Potter, R.I. Barnett, C.E. Koukousakis and C.E. Fisher

Wind-Tunnel Investigations of Wings with Serrated Sharp Trailing Edges 295 P.MH.W. Vijgen, C. P. van Dam, B.I. HoLmes and F.G. Howard

Low Reynolds Number Airfoil Design for Subsonic Compressible Flow 314 RH. Liebeek

Computation of Viscous Unsteady Compressible Flow About Profiles 331 K.Dortmann

Compressible Navier-Stokes Solutions Over Low Reynolds Number Airfoils 343 Z. Alsalihi

Shockffurbulent Boundary Layer Interaction in Low Reynolds Number 358 Supercritical Flows

GR. Inger

Summary of Experimental Testing of a Transonic Low Reynolds Number Airfoil 369 P.L. Toot

The Design of a Low Reynolds Number RPV 381 S. Siddiqi, R. Evangelista and T.S. Kwa

Captive Carry Testing of Remotely Piloted Vehicles 394 A. Cross

Flight Testing Navy Low Reynolds Number (LRN) Unmanned Aircraft 407 R.I. Foeh and P.L. Toot

Vortex Lock-On and Flow Control in Bluff Body Ncar-Wakes 418 O.M. Griffin

Wake Studies on Yawed, Stranded Cables 433 l.v. Nebres, S.M. Balill and R.C. Nelson