IUTAM Symposium on Unsteady Separated Flows and their Control

Unsteady separated flows are an important topic in theoretical and applied mechanics. The IUTAM Symposium held in Corfu in 2007 (and following on from a previous meeting in Toulouse in 2002) aimed at achieving a unified approach which will regroup the knowledge coming from theoretical, experimental, numerical simulation, modeling and flow-control aspects of separated unsteady flows with respect to incompressible and compressible flow regimes. The subject areas are receiving a great deal of impetus from international research groups, stimulated by major research programs related to this topic, involving major industrial companies especially in aeronautics in various countries and by heading government programs. The symposium brought together groups of researchers working on problems related to the understanding and the prediction of unsteady, separated flows. The present IUTAM symposium proceedings volume is an essential extension of the topic to control theory and applications in respect of unsteady separated flows.

Topics addressed include physical aspects of the dynamics related to unsteady separation in incompressible flows and flows under compressibility effects, and the state of the art methods for modeling these kinds of flows in high Reynolds numbers. Special attention is paid to control theory and applications, especially including feed-back effects for the attenuation of unsteadiness and of flow separation. The understanding of the flow-physics and their efficient turbulence modeling remains a serious problem in a number of engineering applications, including Aeronautics and Aeroelasticity. Furthermore, the study of advanced flow modeling techniques, especially to control high-Reynolds number transitional and turbulent flows involving unsteady separation, is a crucial need in the above-mentioned domains of fundamental and applied research nowadays.

This work is of interest to people working in experimental investigation of unsteady separated flows, those working in the numerical simulation and turbulence modeling of these flows and those working in the domain of control theory. The symposium proceedings contributes to a better insight of this important category of flows from a fundamental and applied research point of view by means of a synergy among the three main approaches: theoretical, experimental and prediction methods.

Résumé
This Volume is the Proceedings of the IUTAM Symposium on Unsteady Separated Flows and Their Control held in Corfu, Greece, 1822 June 2007. This was the second IUTAM Symposium on this subject, following the symposium in Toulouse, in April 2002. The Symposium consisted of single plenary sessions with invited lectures, - lected oral presentations, discussions on special topics and posters. The complete set of papers was provided to all participants at the meeting. The thematic sessions of this Symposium are presented in the following: Experimental techniques for the unsteady ow separation Theoretical aspects and analytical approaches of ow separation Instability and transition Compressibility effects related to unsteady separation Statistical and hybrid turbulence modelling for unsteady separated ows Direct and Large-Eddy Simulation of unsteady separated ows Theoretical/industrial aspects of unsteady separated ow control This IUTAM Symposium concerned an important domain of Theoretical and Applied Mechanics nowadays. It focused on the problem of ow separation and of its control. It achieved a uni ed approach regrouping the knowledge provided from theoretical, experimental, numerical simulation and modelling aspects for unsteady separated ows (incompressible and compressible regimes) and included ef cient control devices to achieve attenuation or suppression of separation. The subject - eas covered important themes in the domain of fundamental research as well as in the domain of applications.

Contenu

Experimental Techniques for the Unsteady Flow Separation.- PIV Measurements of the Flow Around Oscillating Cylinders at Low KC Numbers.- Coherent and Turbulent Process Analysis in the Flow Past a Circular Cylinder at High Reynolds Number.- Investigation of Aerodynamic Capabilities of Flying Fish in Gliding Flight.- Effect of Unsteady Separation on an Automotive Bluff-Body in Cross-Wind.- Statistical and Hybrid Turbulence Modeling of Unsteady Separated Flows.- Flow Prediction Around an Oscillating NACA0012 Airfoil at Re = 1,000,000.- Two-Velocities Hybrid RANS-LES of a Trailing Edge Flow.- Assessment of Flow Control Devices for Transonic Cavity Flows Using DES and LES.- Theoretical Aspects & Analytical Approaches of Flow Separation.- Near Critical Phenomena in Laminar Boundary Layers.- State Curves and Flipping for an Orbiting Cylinder at Low Reynolds Numbers.- Global Low-Frequency Oscillations in a Separating Boundary-Layer Flow.- Asymptotic Theory of Turbulent Bluff-Body Separation: A Novel Shear Layer Scaling Deduced from an Investigation of the Unsteady Motion.- Structural Sensitivity of the Finite-Amplitude Vortex Shedding Behind a Circular Cylinder.- Orbiting Cylinder at Low Reynolds Numbers.- A Two-Dimensional Disturbed Flows Over a Flat Plate: Theoretical and Numerical Approach.- Instability and Transition.- Wake Dynamics of External Flow Past a Curved Circular Cylinder with the Free-Stream Aligned to the Plane of Curvature.- Successive Steps of 2D and 3D Transition in the Flow Past a Rotating Cylinder at Moderate Reynolds Numbers.- Direct Numerical Simulation of Vortex Shedding Behind a Linearly Tapered Circular Cylinder.- Dynamics of Oblate Freely Rising Bodies.- Parametric Study of Two Degree-of-Freedom Vortex-Induced Vibrations of a Cylinder in a Two-Dimensional Flow.- Vortex Dynamics Associated with the Impact of a Cylinder with a Wall.- Modification of the Flow Structures in a Swirling Jet.- Thickness Effect of NACA Symmetric Hydrofoils on Hydrodynamic Behaviour and Boundary Layer States.- Quasi-Steady Self-Excited Angular Oscillation of Equilateral Triangular Cylinder in 2-D Separated Flow.- Compressibility Effects Related to Unsteady Separation.- Compressibility Effects on Turbulent Separated Flow in a Streamwise-Periodic Hill Channel-Part 1.- Global Structure of Buffeting Flow on Transonic Airfoils.- Low-Order Modeling for Unsteady Separated Compressible Flows by POD-Galerkin Approach.- Unsteady Flow Organization of a Shock Wave/Turbulent Boundary Layer Interaction.- Dependence Between Shock and Separation Bubble in a Shock Wave Boundary Layer Interaction.- Large Eddy Simulation of a Supersonic Turbulent Boundary Layer at M = 2.25.- Film Cooling Mass Flow Rate Influence on a Separation Shock in an Axisymmetric Nozzle.- Detached Eddy Simulation of a Nose Landing-Gear Cavity.- Experimental and Numerical Study of Unsteady Wakes Behind an Oscillating Car Model.- Physical Analysis of an Anisotropic Eddy-Viscosity Concept for Strongly Detached Turbulent Unsteady Flows.- Dynamic Stall of a Pitching and Horizontally Oscillating Airfoil.- Unsteady Flow Around a NACA0021 Airfoil Beyond Stall at 60° Angle of Attack.- Analysis of Detached-Eddy Simulation for the Flow Around a Circular Cylinder with Reference to PIV Data.- Simulation of Bluff-Body Flows Through a Hybrid RANS/VMS-LES Model.- DNS and LES of Unsteady Separated Flows.- Large Eddy Simulation of Impinging Shock Wave/Turbulent Boundary Layer Interaction at M = 2.3.- Simulation and Modelling of a Laminar Separation Bubble on Airfoils.- Unsteady RANS Calculation of FlowOver Ahmed Car Model.- Effect of Velocity Ratio on the Streamwise Vortex Structures in the Wake of a Stack.- Flow Separation of a Rotating Cylinder.- Theoretical/Industrial Aspects of Unsteady Separated Flow Control.- The Wake Dynamics of a Cylinder Moving Along a Plane Wall with Rotation and Translation.- Simulation Study of the Robust Closed-Loop Control of a 2D High-Lift Configuration.- Large-Eddy Simulation of Passively-Controlled Transonic Cavity Flow…