Sutanu Sarkar – författare

Environmental Turbulence: From Fundamental Physics to Critical Applications explains how to understand environmental and geophysical turbulence, both at a theoretical level and in engineering applications. Sections cover the effects of these new features on the fundamental flow dynamics in relatively simple domains. That is, how the turbulence statistics and structure are modified by the stabilizing or destabilizing effects of buoyancy and rotation is surveyed. Scalar transport is also described in detail. Flow in more complex domains is then described, focusing on vegetated and urban canopies, wind farms, air-sea interfaces, the upper ocean and clouds.Turbulence in environmental media is strongly modulated by buoyancy forces at all scales and by rotation at the largest scales, in contrast to canonical turbulent flows. It is rarely steady, which can give rise to non-equilibrium effects, and the domains such as wind farms or cities are often quite complex, leading to more intricate dynamics than in classic wall-bounded or free shear flows.

Combines a theoretical treatment with detailed coverage of how it is extended to practice in a range of applicationsRe-introduces the reader to the basic fluid mechanics and turbulence knowledge, and then presents their more complex environmental manifestationsCovers in detail six applications that are critical to the grand challenges facing humanity in the 21st century

This book contains contributions by former students, colleagues and friends of Professor John L. Lumley, on the occasion of his 60th birthday, in recognition of his enormous impact on the advancement of turbulence research. A variety of experimental, computational and theoretical topics, including turbulence modeling, direct numerical simulations, compressible turbulence, turbulent shear flows, coherent structures and the Proper Orthogonal Decomposition are contained herein. The diversity and scope of these contributions are further acknowledgment of John Lumley''s wide ranging influence in the field of turbulence. The large number of contributions by the authors, many of whom were participants in The Lumley Symposium: Recent Developments in Turbulence (held at ICASE, NASA Langley Research Center on November 12 & 13, 1990), has presented us with the unique opportu­ nity to select a few numerical and theoretical papers for inclusion in the journal Theoretical and Computational Fluid Dynamics for which Professor Lumley serves as Editor. Extended Abstracts of these pa­ pers are included in this volume and are appropriately marked. The special issue of TCFD will appear this year and will serve as an additional tribute to John Lumley. As is usually the case, the efforts of others have significantly eased our tasks. We would like to express our deep appreciation to Drs. R.

This book contains contributions by former students, colleagues and friends of Professor John L. Lumley, on the occasion of his 60th birthday, in recognition of his enormous impact on the advancement of turbulence research. A variety of experimental, computational and theoretical topics, including turbulence modeling, direct numerical simulations, compressible turbulence, turbulent shear flows, coherent structures and the Proper Orthogonal Decomposition are contained herein. The diversity and scope of these contributions are further acknowledgment of John Lumley's wide ranging influence in the field of turbulence. The large number of contributions by the authors, many of whom were participants in The Lumley Symposium: Recent Developments in Turbulence (held at ICASE, NASA Langley Research Center on November 12 & 13, 1990), has presented us with the unique opportu­ nity to select a few numerical and theoretical papers for inclusion in the journal Theoretical and Computational Fluid Dynamics for which Professor Lumley serves as Editor. Extended Abstracts of these pa­ pers are included in this volume and are appropriately marked. The special issue of TCFD will appear this year and will serve as an additional tribute to John Lumley. As is usually the case, the efforts of others have significantly eased our tasks. We would like to express our deep appreciation to Drs. R.

Stratified flows, common in environmental and geophysical applications, are char­ acterized by the variation of fluid density in the vertical direction that can result in qualitative and quantitative modifications of the flow patterns by buoyancy . Unstable stratification (dense water/air above light water/air) increases the ver­ tical mixing by generation of convective cells while stable stratification generally suppresses vertical mixing of mass and momentum. Even so, a stably stratified fluid can support internal waves, instabilities and turbulence that play a critical role in transport and mixing. The ocean is predominantly subject to stable stratification which, under exter­ nal excitation, supports an environment of internal waves which may then break and generate turbulence. Wind forcing, currents and convective plumes are other sources of turbulence in the ocean. In the ocean, stratified turbulence mediates the upward transport of bottom water, nutrients, chemical and biological species, and pollutants. In the atmosphere, stratification affects the transport of pollutants released at ground level, a critical problem being the thermal inversion in urban areas that causes the stagnation of pollutants and small particulate (PM2.5 to PMIO) in the lower part of the atmospheric boundary layer. In buildings, strat­ ification governs the circulation of air and heat in natural ventilation systems.