The call for papers for the rUTAM-Symposium on Mechanics of Passive and Active Flow Control brought an overwhelming response of applications for contributions. Fi nally 12 invited lectures, 48 papers and 23 posters were selected by thc Scientific Com mittee to be presented in the conference. 58 papers are published in this volume. Due to the limited number of pages available, poster presentations could not be considered for publication. The editors would like to thank all the members of the Scientific Committee for their very valuable assistance. The papers presented at the rUT AM Symposium were classified under three groups de voted to • Passive Control Methods, • Active Control Methods and • Control Concepts. This was done to contrast at first between the passive techniques where the control power is mainly supplied by the flow itself and the active techniques where the power is pro vided by external sources; the third group was devoted to control concepts for presenting methods of control theory and new techniques of flow control.

Zusammenfassung
Proceedings of the IUTAM Symposium held in Goettingen, Germany, 7-11 September 1998

Inhalt
IUTAM Opening Address.- Dynamics and Control of Near-Wall Coherent Structures.- I. Passive Control Methods Session 1.- Flow Physics Involved in Shock Wave/Boundary Layer Interaction Control.- Shock/Boundary Layer Control by Various Concepts.- Expansion Shoulder Bump for Wing Section Viscous/Wave Drag Control.- Euroshock I and II: A Survey.- A Review of Flow Control Research at DERA.- Assessment of the Capability of Drag Reduction of the Shock Control Device' SC Bump' on Airfoil Flows and Application Aspects on Wings.- Passive Control of Buffet Excitation.- Enhanced Thrust-Efficiency of Overexpanded Nozzles by Passive Venting.- The Control of Compressible Dynamic Stall Using Adaptive Airfoils.- Application of Micro-Vortex Generators for Turbulent Flow Separation Control.- Fundamental Investigations of the Flow about Devices Suitable for Use in Flow Control.- A Novel Use of Vortex Generators for Separation Control in the Corner between a Wall and a Wing.- Windtunnel Experiments with Artificial Bird Feathers for Passive Separation Control on Airfoils.- A Method of Mixing Process Control in a Shear Layer of a Supersonic Nonisobaric Jet.- Passive control methods: riblets, vortex generators and self-activating flaps.- Natural Riblets.- The Flow over Riblets: Velocity Measurements with Hot-Film Probes.- Numerical Investigation of Flow around Vented Sphere.- Drag Reduction of a Sphere at Supercritical Reynolds Numbers Using Passive Ventilation.- Separation Control of a Thin Airfoil by Projectile Vortex Rings.- Turbulence Reduction in the Initial Region of a Plane Jet Using Passive Control.- Influence of Riblets on a Supersonic Wake Flow.- II Active Control Methods Session 1.- Receptivity Issues for Laminar-Flow Control.- Control of Boundary Layer Transition at High FST byLocalized Suction.- Experiments on the Control of Crossflow Instability with the Aid of Suction through Perforated Walls.- Control of Crossflow Instability Field by Selective Suction System.- Control of the Laminar-Turbulent Transition by a Suction of the Boundary Layer in 2D Flow.- Control of Transition in 3-D Boundary Layers.- Transition Control Using Leading Edge Roughness for the ONERA-D Wing.- Active Flow Control by Micro Systems.- Strategy of the Flow Mems Control at Laminar-Turbulent Transition in a Boundary Layer.- Manipulating Coherent Structures by Heat in a Boussinesq Jet.- Boundary Layer Control over an Active Ribleted Surface.- Control of Coherent Structures Shedding and Generation of Sound in Bluff-Body Wake Flow.- Oscillations of Solid Surfaces versus Sound and Oscillatory Suction in Flow Control.- Theoretical and Computational Study of the Wake Control Problem.- Moving Surface Separation Control for Airfoil at High Angles of Attack.- Separation Control on an Airfoil under Post-Stall Conditions by Mechanical Excitation.- Effect of Microbubble Cluster on Turbulent Flow Structure.- Stability Analysis of the Wake Control Problem.- Control of the Periodic Near Wake behind a Plane Blunt Base.- Aerodynamic Flow Control of Bluff Bodies Using Synthetic Jet Actuators.- Reduction of Unsteady Forces on Bluff Bodies Using Rotating Control Cylinders.- Moving Surface Boundary-Layer Control as Applied to Slender and Bluff Bodies.- Flow Control by Periodic Forcing: Acoustic Excitation and Local Injection of Artificial Disturbances.- Control of the Leading-Edge Separation from an Airfoil by Internal Acoustic Excitation and Self-Induced Resonances.- Control of Pipe Flow by Use of an Aeroacoustic Instability.- Near Wall Turbulence Reaction to a Localized Time-Periodical Blowing.- Manipulation of Trailing Edge Separation on an Aerofoil Using a Periodic Cross-Flow.- Transition Control of Supersonic Boundary Layer on Flat Plate.- III. Control Concepts Session 1.- Active Control of Turbulent Boundary Layers for Drag Reduction.- The Effects of Flow Instabilities on the Active Control of Separation.- Active Control of Kelvin-Helmholtz Waves.- Dynamic Control of the Jet-Edge-Flow.- A Low-Order Model-Following Strategy for Active Flow Control.- List of Participants.- Author Index.