This book contains the proceedings of a colloquium held in Monte Verità from September 9-13, 1991. Special care has been taken to devote adequate space to the scientific discussions, which claimed about half of the time available. Scientists from all over the world presented their views on the importance of kinematic properties, topology and fractal geometry, and on the dynamic behaviour of turbulent flows. They debated the importance of coherent structures and the possibility to incorporate these in the statistical theory of turbulence, as well as their significance for the reduction of the degrees of freedom and the prospective of dynamical systems and chaos approaches to the problem of turbulence. Also under discussion was the relevance of these new approaches to the study of the instability and the origin of turbulence, and the importance of numerical and physical experiments in improving the understanding of turbulence.
Table of ContentsOpening Address.- Session One..- Similarity Laws for Wall Turbulent Flows: Their Limitations and Generalizations.- A Prediction of the Multifractal Model: The Intermediate Dissipation Range.- A New View of Developed Turbulence.- Discussion.- Session Two..- On Vortices And Cascades in Turbulence.- A Dynamical Theory of Cascade in Turbulence and Non-Gaussian Statistics.- Small Scale Vortices in Turbulent Flows.- Discussion.- Session Three..- Spiral Structures in Turbulent Flow.- Solutions of Exact Kinetic Equations for Intermittent Turbulence.- How Important are Direct Interactions between Large and Small Scales in Turbulent Flows.- Discussion.- Session Four..- How Long is the Way from Chaos to Turbulence?.- Vortex Interactions as a Dynamical System.- Finite-dimensional Dynamics and Chaos in Fluid Flows.- Discussion.- Session Five..- The Origins of Turbulence.- Role of Algebraic Instability in Transition and Turbulence.- Active Control of Skin Friction and Separation in Certain Class of Wall-Bounded Flows.- Rapid Distortion Theory and the Structure of Turbulence.- Discussion.- Session Six..- A New Approach for Large Eddy Simulation of Turbulence and Scalar Transport.- On the Contribution of Multi-Point Experimental Techniques to the Study of Turbulence.- Direct Numerical Simulations and Hot Wire Experiments: A Possible Way Ahead?.- Small-Scale Structures in Turbulence: Their Implications for Turbulence Closures.- A Note on Local Isotropy in High-Reynolds-Number Turbulence.- Discussion.- Group Work.- Group I: Prospects of physical and numerical experiments for the fundamental understanding of turbulence.- Group II: Future implications of chaos theory, dynamical systems and prospects of low-dimensional descriptions of turbulent flows.- Group III: Reduction of non-linearity in turbulent flows further lines of research and their use in the development of the theory of turbulence.- Group IV: Prospects of statistical approaches to the turbulence problem how statistical methods, e.g. the theory of random fields, should be used in view of recent developments regarding the structure of turbulence, dynamical chaos, strange attractors, fractals.- Summary of the Symposium.- Discussion.