Disorder and Mixing

CARGESE INSTITUfE ON DISORDER AND MIXING Convection, diffusion and reaction are the three basic mechanisms in physico-chemical hydrodynamics and chemical engineering. Both convective and diffusive processes are strongly influenced by the effect of disorder of granular matter in porous media, suspensions, fluidized beds or/and by the randomness caused in turbulent flow field. This book has been initiated by a NATO summer institute held in Cargese (Corsica, FRANCE) from June 15 th to 27 th 1987 . Its aim was to associate statistical physicists, fluid mechanicians and specialists of chemical engineering on the problems of the relation between disorder and mixing and, in this respect, this is a " premiere ". This book is made of chapters based on lectures given in the meeting. However we have paid a considerable attention to harmonize the contents and styles of chapters made by scientists trained in different communities and using different languages and techniques to describe similar problems. The Prelude by the editors of the book introduces the different points and is a biased view of some of the important and most active aspects of the subjects developed. We wish to thank all contributors and students of the institute who gave the style of the present interdisciplinary approach. We also greatly thank Elisabeth Charlaix who has shared with us the scientific and practical organisation of the institute, and Marie-France Hanseler for her technical support.

Inhalt

Basics.- I. Part A: Introduction to random walks.- B: The physical mechanisms of anomalous diffusion.- II. Fractals and multifractals in physics.- III. Hydrodynamics at low Reynolds numbers: a brief and elementary introduction.- IV. Some chemical engineering problems related to mixing and disorder.- Short contribution: 1. Chemical dissolution of a porous medium: experiments and computer simulations.- Dispersion.- V. Experimental study of tracer dispersion in model and natural porous media.- VI. Dispersion in porous media.- VII. Hydrodynamic dispersion in random networks.- VIII. Pollutant dispersion in oceans.- Short contributions: 2. Diffusive transport in laminar flows.- 3. Diffusive transport in the Rayleigh-Benard convective flow.- 4. Logarithmic effects in longitudinal dispersion in porous media.- Suspensions.- IX. Sedimentation of small particles.- X. Filtration processes.- XI. Aspects of flow and mixing behavior in fluidized beds.- Mixing in complexe situations.- XII. Transport of polymers.- XIII. Mass transfer and reaction in fixed-bed heterogeneous systems: application to sorption operations and catalytic reactors.- XIV. The effect of dispersion on fingering in miscible displacements.- XV. Two phase flow through packed bed static and dynamic accessibilities of the packing.- Short contributions: 5. Mixing in agitated vessels: a random-walk approach.- 6. Elastohydrodynamic collisions and bouncing of spherical particles.- 7. Hintered settling and hydrodynamic dispersion of sedimenting spheres.- Turbulence and reactions.- XVI. Molecular mixing and chemical reactions in turbulent shear flows.- XVII. Theory of flames.- Short contribution: 8. Intermittency in boundary layer.- Techniques.- XVIII. Magnetic resonance imaging of liquids in porous media: a comparison to other visualization techniques.- XIX. Stereological analysis of condensed materials.- Conclusion.- XX. Lagrangian mixing.- Index of key words.