Eddy Structure Identification in Free Turbulent Shear Flows

The existence and crucial role played by large-scale, organized motions in turbulent flows are now recognized by industrial, applied and fundamental researchers alike. It has become increasingly evident that coherent structures influence mixing, noise, vibration, heat transfer, drag, etc... The accelera tion of the development of both experimental and computational programs devoted to this topic has been evident at several recent international meet ings. One of the first questions which experimentalists or numerical analysts are faced with is: how can these structures be separated from the background turbulence? This is a nontrivial task because the coherent structures are gen erally embedded in a random field and the technique used to determine when and where certain structures are passing, or their averaged characteristics (in the more probable or dominant role sense) is directly related to the definition of the coherent structure. Several methods or approaches are available and the choice of a particular one is generally dependent on the desired informa tion. This choice depends not only on the definition of the structure, but also on the experimental and numerical capabilities available to the researcher.

Inhalt
Introductory Remarks to the IUTAM Conference and ERCOFTAC Workshop on Eddy Structure Identification for Free Shear Flows.- Organised Eddies in Turbulent Shear Flows.- I. Large and Small Scale Dynamics.- New Approaches to Vortex Dynamics: Core Dynamics, Helical Waves, and Interaction with Fine Scale Turbulence.- Impulse Analysis of Fractal and Multifractal Structure of the Field of Derivatives in Turbulent Flows.- The Genesis of Longitudinal Vortices in Free and Bounded Shear Layers.- II. Conditional Sampling I: Vorticity-based Methods.- Vorticity-based Conditional Sampling for Identification of Large-Scale Vortical Structures in Turbulent Shear Flows.- Eduction of Coherent Structures in a Numerically Simulated Plane Wake.- Acoustic Control of Vortical Structure in a Plane Jet.- III. Conditional Sampling II: Other Methods.- Large Scale Structure Characterization in a 2D Mixing Layer by Pseudo-Flow-Visualization and Delocalized Conditional Sampling.- Identification of Low-Speed Spots and Vortical Structures in the Wake of a Long Cylinder in a Near-Axial Flow.- On The Influence of Initial Parameters on Subharmonic Res onance in an Axisymmetric Jet.- Eduction of Vortical Structures by Pressure Measurements in Noncircular Jets.- A Study of Flow Properties Near Critical Points.- IV. Wavelets.- Wavelet Analysis of Fractal Signals: Application to Fully Developed Turbulence Data.- Experimental Analysis of Coherent Motions in a Turbulent Boundary Layer.- On the Use of 2D Wavelets for the Analysis of Coherent Structures.- V. Pattern Recognition Analysis.- Analysis of Turbulent Signals.- Pattern Recognition Analysis of Structure in Manipulated Channel Flow Simulations.-VI. Proper Orthogonal Decomposition.- Detection of Self-Similar Modes in Turbulence: Application to a Wake Flow.- Characterization of the Organization in Shear Layers via Proper Orthogonal Decomposition.- Near-Wall Reconstruction of Higher-Order Moments and Length Scales Using the POD.- The Application of Classical POD and Snapshot POD in a Turbulent Shear Layer With Periodic Structures.- Free Shear Flow Coherent Structures in a Low-Dimensional Eigenfunction Space.- VII. Stochastic Estimation.- Stochastic Estimation of Conditional Structure.- Stochastic Estimation of Multipoint Conditional Averages and Their Spatio-Temporal Evolution.- VIII. Combined or Comparative Approaches.- The Proper Orthogonal Decomposition, Wavelets and Modal Approaches to the Dynamics of Coherent Structures.- A Comparison of Different Analytical Techniques For Iden tifying Structures in Turbulence.- An Examination of the Axisymmetric Jet Mixing Layer using Coherent Structure Detection Techniques.- IX. Topological Concepts.- Topology of Flow Patterns in Vortex Motions and Turbulence .- Instability Patterns, Wakes and Topological Limit Sets.- Identification and Classification of Topological Structures in Free Shear Flows.- X. Full Field Methods.- Visualization and Identification of Vortex Structures in Stratified Wakes.- Application of Digital Particle Image Velocimetry to a Turbulent Pipe Flow.- Coherent Structures in a Simulated Turbulent Mixing Layer.- Identification of Zones in a Free Evolving Vortex Ring.- XI. Compressible Flows.- Coherent Structures in Shear Flows, Chemical Tracers and Turbulent Combustion.- Supersonic Mixing Layer Analysis by Laser Planogram and Hot-Wire basedPOD.- Flow Visualization in Compressible Turbulent Shear Layers.- Identification of Large Structures in Compressible Mixing Layers Using Filtered Rayleigh Scattering.- List of Participants.- Author Index.