Since the inaugural symposium at the Pennsylvania State University in 1977, the venues for the series of biennial symposia on turbulent shear flows have alternated between the USA and Europe. For the Sixth Symposium, the first to be held in France, the city of Toulouse proved a natura] choice, being a centre for the aerospace industry, meteorological research and higher education. The meeting was hosted by the Paul Sabatier University on the southern perimeter of the city, and there nearly 300 workers in the field of turbulence converged to pronounce upon, debate and absorb the current issues in turbulent shear flows and to enjoy the unfailing September sunshine. The meeting had attracted more than 200 offers of papers from which just over 100 full papers and about 20 shorter communications in open forums could be accommodated. The present volume contains 28 of the original symposium presentations selected by the editors. Each contribution has been revised by its authors - sometimes quite extensively -in the light of the oral presentation. It is our hope that the selection provides a substantial statement of permanent interest on current research in the five areas covered by this book, i.e. fundamentals and closures, scalar transport and geophysical flows, aerodynamic flows, complex flows, and numerical simulations.

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.

This book provides state-of-the-art results and theories in homogeneous turbulence, including anisotropy and compressibility effects with extension to quantum turbulence, magneto-hydodynamic turbulence and turbulence in non-newtonian fluids. Each chapter is devoted to a given type of interaction (strain, rotation, shear, etc.), and presents and compares experimental data, numerical results, analysis of the Reynolds stress budget equations and advanced multipoint spectral theories. The role of both linear and non-linear mechanisms is emphasized. The link between the statistical properties and the dynamics of coherent structures is also addressed. Despite its restriction to homogeneous turbulence, the book is of interest to all people working in turbulence, since the basic physical mechanisms which are present in all turbulent flows are explained. The reader will find a unified presentation of the results and a clear presentation of existing controversies. Special attention is given to bridge the results obtained in different research communities. Mathematical tools and advanced physical models are detailed in dedicated chapters.

A collection of contributions on a variety of mathematical, physical and engineering subjects related to turbulence. Topics include mathematical issues, control and related problems, observational aspects, two- and quasi-two-dimensional flows, basic aspects of turbulence modeling, statistical issues and passive scalars.