Advances in Turbulence 2 Proceedings of the Second European Turbulence Conference Berlin, August 30 – September 2, 1988

The Second European Turbulence Conference was held at the Technische Univer­ sitat Berlin, Federal Republic of Germany, from August 30th to September 2nd 1988 under the auspices of the European Mechanics Committee. It was primar­ ily devoted to fundamental aspects of turbulence, and aimed at bringing together engineers, physicists, and mathematicians. The scientific committee - serving also as Sub-committee of the European Turbulence Conference - consisted of the following members: G. Comte-Bellot (Lyon), H.-H. Fernholz and H.E. Fiedler (both from Berlin) as co-chairmen of the conference, U. Frisch (Nice), J.C.R. Hunt (Cambridge), E. Krause (Aachen), M. Landahl (Stockholm), A.M. Obukhov (Moscow), and G. Ooms (Amsterdam). The conference programme comprised 6 invited lectures and 94 contributions, presented either orally or at poster sessions. There were 165 participants from 18 countries. All papers published in these conference proceedings were, with the exception of the invited ones, again refereed by the members of the scientific committee. The main research topics discussed at this meeting were stability and gener­ ation of turbulence, effects of rotation, stratification and buoyancy forces, novel instrumentation, manipulation and control, boundary layers with separation and reattachment, computer simulation, turbulent diffusion, image analysis and flow visualization, vorticity dynamics and turbulence, and large-scale structures. We have taken the liberty of regrouping some papers following the submitted final versions for this volume. Authors may therefore find their paper under a different heading from that in the conference programme.

I Stability and Transition.- On the Spreading Mechanism of a Turbulent Spot in Plane Poiseuille Flow.- An Experimental Study of the Velocity Field of Turbulent Spots in Plane Poiseuille Flow.- Discrete Stages of Laminar—Turbulent Transitions in a Wall-Bounded Flow — An Aspect of the Symmetry of Certain Patterns of Turbulence.- On the Internal Order and Structures in a Transitional Spot.- II General Structure, Coherent Structures and Vortex Dynamics.- Some Remarks on the Probability Distribution of ?u/?t in Turbulent Flow.- Coherent Structures and the Turbulent Prandtl Number.- Transition Processes of Mixing Layers.- The Dynamics of Vortex Rings in an Unbounded Domain.- Multiple Large-Scale Coherent Structures in Free Turbulent Shear Flows.- Three-Dimensional Vorticity Dynamics in the Near Wake Behind Two-Dimensional Bodies.- On the Possibility of an Inverse Cascade in Three-Dimensional Anisotropic Flows Lacking Parity Invariance.- III Free Shear Flows.- The Statistical Properties of the Vorticity Field of a Two-Stream Turbulent Mixing Layer.- Formation of Helical Structures in a Round Free Jet.- Measurement and Modeling of Anisotropic Turbulent Flows.- Vorticity Based Intermittency Measurements in a Single Stream Shear Layer.- Subharmonic Resonance in a Shear Layer.- Large-Eddy Interpretation of LDA Results Obtained by Conditional Seeding in a Circular Jet.- Entrainment in Free Turbulent Flows.- IV Wall-Bounded Flows.- Turbulent Flow over Two-Dimensional, Surface-Mounted Obstacles: Plane and Axisymmetric Geometries.- Propagation of Small Perturbations Through the Structure of Turbulence in a Wall Boundary Layer.- Cross Correlation and Length Scales in Turbulent Flows near Surfaces.- On the Relation Between Sweeps and Streamwise Vortices.- Experimental Data on Wall Turbulence in Bubble Flows.- A New Modelling Approach to Complex Turbulent Shear Flows.- V Turbulent Diffusion, Effects of Rotation, Stratification, and Buoyancy.- Phase Turbulence in Fluid Systems.- Spectral Approach to Axisymmetric Turbulence in a Stratified Fluid.- Experimental Study of Rotation Effects on Grid Generated Turbulence with Different Mesh Sizes.- Turbulent Diffusion in a Stratified Fluid.- Cross-Spectral Properties of Large Eddies in the Stably Stratified Atmospheric Boundary Layer.- Molecular and Stratification Effects on the Evolution of Concentration Fluctuations in Decaying Homogeneous Turbulence with Transverse Mean-Concentration Gradient.- Turbulent Diffusion from Thermal or Reactive Sources: Numerical Experiment.- Internal and External Mixing in Stratified-Shear Flow.- Free Convection Grid Turbulence.- Heat Transfer by Thermals in the Convective Boundary Layer.- Turbulent Diffusion.- VI Experimental Methods and Instrumentation.- Turbulence Experiments — Instrumentation and Processing of Data.- A Turbulent Wall Layer Visualization System Using a Dense Fog and a Scanning Laser Beam.- Analysis of Structures in a Turbulent, Plane Mixing Layer by Use of a Pseudo Flow Visualization Method Based on Hot-Wire Anemometry.- Skin Friction Measurements by Dual Laser-Beam Interferometry.- On Turbulence Measurements with a Split-Film Probe.- Vorticity Measurements in a Turbulent Mixing Layer.- Flow Structure Analysis by Laser Rayleigh Techniques.- Analyzing 3-D Turbulent Motions in Open Channel Flow by Use of Stereoscopy and Particle Tracking.- Particle Tracking in Turbulent Flows.- A New Hot-Wire Technique for Measuring the Instantaneous Velocity Vector in Highly Turbulent Flow.- Measurements of Instantaneous Flow Angles by Optical Detection of the Thermal Wake of a Hot Wire.- VII Numerical Methods: Direct Computer Simulations, Large-Eddy Simulations and Closure Predictions.- Pressure-Strain Rate Events in Homogeneous Turbulent Shear Flow.- A New Strategy for Hydrodynamics — Lattice Gases.- Particle Trajectories in Turbulent Flow Generated by True-Varying Random Fourier Modes.- Turbulence Model Data Derived from Direct Numerical Simulations.- Simulating Vortex Interaction by Three-Dimensional Vortex Method.- The Prediction of Force Field Effects on Turbulent Shear Flows via Second-Moment Closure.- An Eddy Damped Quasi Normal Markovian Approach to Compressible Isotropic and Homogeneous Turbulence.- Three-Dimensional Simulation of Taylor-Couette Flow.- Large Eddy Simulations of Isotropic and Stably-Stratified Turbulence.- Computation of Turbulent Boundary Layer Flow with Separation — A Critical Evaluation of Parameters Influencing the Numerical Results.- Direct Simulation of Flow Structures Initiated by a Rotating Cover in a Cylindrical Vessel.- Statistical Treatment of Many Vortex Systems.- 1283 Harmonics Direct Simulation of Homogeneous Rotated Turbulence.- On the Geometry of Lines in Two-Dimensional Turbulence.- Some Numerical Studies of Turbulent Wake over Hills.- Large-Eddy Simulation of Turbulent Flow over a Square Rib in a Channel.- VIII Manipulation and Control of Turbulence.- Pressure Gradient Effect on the Turbulence Structure over Riblet Surface.- Generation of and Measurements in a Turbulent Boundary Layer with Zero Skin Friction.- On the Mechanism Involved in a Turbulent Boundary Layer over Riblets.- The Spanwise Confined One-Stream Mixing Layer.- Structures in a Turbulent Boundary Layer.- Experiments on the Absolute Instability of Heated Jets.- On the Spanwise Structure of a Plane Mixing Layer.- The Mixing Layer Between Non-parallel Walls.- The Influence of Drag Reduction Additives on the Coherent Structures in a Free Shear Layer.- IX Applications.- Influence of Shear Layer Induced Fluctuations on the Velocity Unsteadiness in Free-Jet Wind Tunnels.- Turbulence and the Process Industry.- Flow Visualization of the Disk-Cylinder Configuration.- List of Participants.- Index of Contributors.