This book contains a collection of the main contributions from the first five workshops held by Ercoftac Special Interest Group on Synthetic Turbulence Models (SIG42. It is intended as an illustration of the sig's activities and of the latest developments in the field.

Thisvolume investigates the use of Kinematic Simulation (KS) and other synthetic turbulence models for the particular application to environmental flows.

Thisvolume offers the best syntheses on the research status in KS, which iswidely used in various domains, including Lagrangian aspects in turbulence mixing/stirring, particle dispersion/clustering, and last but not least, aeroacoustics. Flow realizations with complete spatial, and sometime spatio-temporal, dependency, are generated via superposition of random modes (mostly spatial, and sometime spatial and temporal, Fourier modes), with prescribed constraints such as: strict incompressibility (divergence-free velocity field at each point), high Reynolds energy spectrum. Recent improvements consisted in incorporating linear dynamics, for instance in rotating and/or stably-stratified flows, with possible easy generalization to MHD flows, and perhaps to plasmas. KS for channel flows have also been validated. However, the absence of "sweeping effects" in present conventional KS versions is identified as a major drawback in very different applications: inertial particle clustering as well as in aeroacoustics. Nevertheless, this issue was addressed in some reference papers, and merits to be revisited in the light of new studies in progress. "

This book contains a collection of the main contributions from the first five workshops held by Ercoftac Special Interest Group on Synthetic Turbulence Models (SIG42. It is intended as an illustration of the sig s activities and of the latest developments in the field.

Thisvolume investigates the use of Kinematic Simulation (KS) and other synthetic turbulence models for the particular application to environmental flows.

Thisvolume offers the best syntheses on the research status in KS, which iswidely used in various domains, including Lagrangian aspects in turbulence mixing/stirring, particle dispersion/clustering, and last but not least, aeroacoustics. Flow realizations with complete spatial, and sometime spatio-temporal, dependency, are generated via superposition of random modes (mostly spatial, and sometime spatial and temporal, Fourier modes), with prescribed constraints such as: strict incompressibility (divergence-free velocity field at each point), high Reynolds energy spectrum. Recent improvements consisted in incorporating linear dynamics, for instance in rotating and/or stably-stratified flows, with possible easy generalization to MHD flows, and perhaps to plasmas. KS for channel flows have also been validated. However, the absence of "sweeping effects" in present conventional KS versions is identified as a major drawback in very different applications: inertial particle clustering as well as in aeroacoustics. Nevertheless, this issue was addressed in some reference papers, and merits to be revisited in the light of new studies in progress. "

The modern understanding of turbulence is that it is a collection of weakly correlated vortical motions, which, despite their intermittent and chaotic distribution over a wide range of space and time scales, actually consist of local characteristic 'eddy' patterns that persist as they move around under the influences of their own and other eddies' vorticity fields. Numerical simulations and experimental observations have now identified some forms and elements of 'life-cycles' of some of these structures. The articles in this volume, first published in 2000, examine a number of key questions that have engaged turbulence researchers for many years. Most involve mathematical analysis, but some describe numerical simulations and experimental results that focus on these questions. However, all are addressed to a wide cross-section of the turbulence community, namely mathematicians, engineers and scientists.

The dynamics of many nonlinear systems gravitate around a few common central themes: intermittency, order/coherence and disorder. These features affect scalings and lead to deviations from Gaussian behaviour. Intermittency may be the universal outcome of a large class of nonlinear systems; however the universality properties of specific nonlinear systems, that is the dependencies of the intermittent structure on initial and boundary conditions, remain open questions. This volume consists of articles by prominent figures who all participated in a workshop held at the Newton Institute in Cambridge. It reflects the aims of the workshop, namely to capture and summarise recent developments, encourage cross-fertilisation of ideas, lay out research directions for the future and provide an overview of our current understanding of the subject.

The dynamics of many nonlinear systems gravitate around a few common central themes: intermittency, order/coherence and disorder. Intermittency may be the universal outcome of a large class of nonlinear systems; however, the universality properties of specific nonlinear systems remain open questions. This volume consists of articles by leading figures who all participated in a workshop held at the Newton Institute in Cambridge.

The articles in this volume, derived from a symposium held at the Newton Institute in Cambridge, examine a number of key questions that have engaged turbulence researchers for many years. Most involve mathematical analysis, but some describe numerical simulations and experimental results that focus on these questions. However, all are addressed to a wide cross-section of the turbulence community, namely mathematicians, engineers and scientists.