A. Gyr – författare

In regions as densely populated as Western Europe, prediction of the ecological implications of pollutant transport are important in order to minimise damage in the case of accidents, and to evaluate the possible influence of existing or planned sources. In most cases, such predictions depend on high-speed computation. This textbook presents a mathematically explicit introduction in eight chapters: 1: An introduction to the basics of fluid dynamics of the atmosphere and the local events and mesoscale processes. 2: The types of PDEs describing atmospheric flows for limited area models, the problem of appropriate boundary conditions describing the topographical constraints, and well-posedness. 3: Thermodynamics of the atmosphere, dry and wet, its stability, and radiation processes, budgets and the influence of their sum. 4: Scaling and similarity laws for stable and convective turbulent atmospheric boundary layers and the influence of inhomogeneous terrain on the advection and the vertical dispersion, and the method of large eddy simulation. 5: Statistical processes in turbulent dispersion, turbulent diffusion and chemical reactions in fluxes.6: Theoretical modelling of diffusion and dispersion of pollutant gases. 7: The influence of urban heat production on local climate. 8: Atmospheric inversion layers and lapping inversion, the stable boundary layer and nocturnal inversion.

This text shows how fibres, polymer molecules or surfactants at very dilute concentrations can reduce the drag of turbulent flow, leading to energy savings. The dilute solutions are considered in terms of the physical chemistry and rheology, and the properties of turbulent flows are presented in sufficient detail to explain the various interaction mechanisms. The text may be useful reading for those active in fundamental research on turbulence and those seeking to apply the effects described.

This text promotes the interdisciplinary work between science and art - in the present volume specifically the interaction of fluid dynamics and video art. It suggests how both disciplines can profit from each other without loss of professionality in either field. Both disciplines are described in their own language. The contributions in fluid mechanics are from internationally well-known scientists, and the topics range from fractal laminar flows in the lung to astrophysical processes. Turbulence, vortex dynamics, bio-fluid dynamics as well as issues in magnetohydromechanics and topological fluid dynamics compete with more than a dozen artworks by known Dutch and Swiss video artists. The catalogue of the exhibition incorporated in the book illustrates how artistic creativity can profit from scientific results, and how scientists can learn from artists how to present their thoughts and ideas.

It is evident, that for a number of ecological and technical problems in rivers and lakes a better knowledge of sediment transport and sedimentation is needed together with the ability to predict and simulate sediment behaviour. On the other hand, a stagnation of research in these topics could be observed in the last decades. This proceedings volume presents up-to-date results in mathematics and natural sciences relevant for the sediment problem. Alternative strategies were discussed to tackle the complexity of the problem. Basic theoretical research and laboratory experiments alone are incomplete without a feedback from field observations and measurements. For that reason well-known researchers from both basic and engineering sciences were invited. Turbulence, non-local phenomena, stability, interaction, feedback systems, self-organization, two-phase flow and chaotic processes, numerical simulations as well as measurement techniques and field results were the keywords of the symposium.

In regions as densely populated as Western Europe, prediction of the ecological implications of pollutant transport are important in order to minimise damage in the case of accidents, and to evaluate the possible influence of existing or planned sources. In most cases, such predictions depend on high-speed computation. The present textbook presents a mathematically explicit introduction in eight chapters: 1: An introduction to the basics of fluid dynamics of the atmosphere and the local events and mesoscale processes. 2: The types of PDEs describing atmospheric flows for limited area models, the problem of appropriate boundary conditions describing the topographical constraints, and well-posedness. 3: Thermodynamics of the atmosphere, dry and wet, its stability, and radiation processes, budgets and the influence of their sum. 4: Scaling and similarity laws for stable and convective turbulent atmospheric boundary layers and the influence of inhomogeneous terrain on the advection and the vertical dispersion, and the method of large eddy simulation. 5: Statistical processes in turbulent dispersion, turbulent diffusion and chemical reactions in fluxes.6: Theoretical modelling of diffusion and dispersion of pollutant gases. 7: The influence of urban heat production on local climate. 8: Atmospheric inversion layers and lapping inversion, the stable boundary layer and nocturnal inversion.

Drag Reduction of Turbulent Flows by Additives is the first treatment of the subject in book form. The treatment is extremely broad, ranging from physicochemical to hydromechanical aspects. The book shows how fibres, polymer molecules or surfactants at very dilute concentrations can reduce the drag of turbulent flow, leading to energy savings. The dilute solutions are considered in terms of the physical chemistry and rheology, and the properties of turbulent flows are presented in sufficient detail to explain the various interaction mechanisms. Audience: Those active in fundamental research on turbulence and those seeking to apply the effects described. Fluid mechanical engineers, rheologists, those interested in energy saving methods, or in any other application in which the flow rate in turbulent flow should be increased.

It is evident, that for a number of ecological and technical problems in rivers and lakes a better knowledge of sediment transport and sedimentation is needed together with the ability to predict and simulate sediment behaviour. On the other hand, a stagnation of research in these topics could be observed in the last decades. At the Symposium an attempt was made to present new results in mathematics and natural sciences relevant for the sediment problem. New strategies were discussed to tackle the complexity of the problem. Basic theoretical research and laboratory experiments alone are incomplete without a feedback from field observations and measurements. For that reason well-known researchers from both basic and engineering sciences were invited. Turbulence, non-local phenomena, stability, interaction, feedback systems, self-organization, two-phase flow and chaotic processes, numerical simulations as well as measurement techniques and field results were the keywords of the Symposium. This proceedings are a good source for those interested in the state of the art.

Presenting research on reactive flows, this work covers theoretical aspects, experimental techniques and the development of models implemented in computational fluid dynamics software.