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Hydrodynamic processes at the water-sediment interface of streambeds

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Book Series: Dissertationsreihe am Institut für Hydromechanik der Universität Karlsruhe / Universität Karlsruhe (TH), Institut für Hydromechanik ISSN: 14394111 ISBN: 9783866442443 Year: Volume: 2008/1 Pages: IV, 153 p. DOI: 10.5445/KSP/1000008267 Language: GERMAN
Publisher: KIT Scientific Publishing
Subject: General and Civil Engineering
Added to DOAB on : 2019-07-30 20:02:00
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Simultaneous 2D pressure and 2D velocity information at the rough water-sediment interface of streambeds were gained by a newly developed measurement setup. In the bed the pressure fluctuations decay exponentially within the first 1-2 equivalent sand roughnesses. Structural findings concerning coherent flow structures are consistent with models originally developed for smooth walls. A significant bed destabilizing flow-pressure pattern was identified for the first time.

Simulation of Turbulent Flows with and without Combustion with Emphasis on the Impact of Coherent Structures on the Turbulent Mixing

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ISBN: 9783731504085 Year: Pages: XXXI, 215 p. DOI: 10.5445/KSP/1000047969 Language: ENGLISH
Publisher: KIT Scientific Publishing
Subject: Chemical Engineering
Added to DOAB on : 2019-07-30 20:02:02
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The analysis of turbulent mixing in complex turbulent flows is a challenging task. The effective mixing of entrained fluids to a molecular level is a vital part of the dynamics of turbulent flows, especially when combustion is involved. The work has shown the limitations of the steady-state simulations and acknowledged the need of applying high-fidelity unsteady methods for the calculation of flows with pronounced unsteadiness promoted by large-scale coherent structures or other sources.

Optimizing Dual-Doppler Lidar Measurements of Surface Layer Coherent Structures with Large-Eddy Simulations

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Book Series: Wissenschaftliche Berichte des Instituts für Meteorologie und Klimaforschung des Karlsruher Instituts für Technologie ISSN: 01795619 ISBN: 9783731501978 Year: Volume: 64 Pages: 234 p. DOI: 10.5445/KSP/1000039726 Language: ENGLISH
Publisher: KIT Scientific Publishing
Subject: Astronomy (General)
Added to DOAB on : 2019-07-30 20:02:02
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Coherent structures are patterns in the wind field of the atmospheric boundary layer. The deployment of two scanning Doppler lidars facilitates the measurement of the horizontal wind field, but the inherent averaging processes complicate an interpretation of the results. To assess the suitability of this technique for coherent structure detection large-eddy simulations are used as a basis for virtual measurements, and the effects of the lidar technique on the wind field structure are analyzed.

Intermittency and Self-Organisation in Turbulence and Statistical Mechanics

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ISBN: 9783039211081 / 9783039211098 Year: Pages: 298 DOI: 10.3390/books978-3-03921-109-8 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Science (General) --- Mathematics
Added to DOAB on : 2019-08-28 11:21:27
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There is overwhelming evidence, from laboratory experiments, observations, and computational studies, that coherent structures can cause intermittent transport, dramatically enhancing transport. A proper description of this intermittent phenomenon, however, is extremely difficult, requiring a new non-perturbative theory, such as statistical description. Furthermore, multi-scale interactions are responsible for inevitably complex dynamics in strongly non-equilibrium systems, a proper understanding of which remains a main challenge in classical physics. As a remarkable consequence of multi-scale interaction, a quasi-equilibrium state (the so-called self-organisation) can however be maintained. This special issue aims to present different theories of statistical mechanics to understand this challenging multiscale problem in turbulence. The 14 contributions to this Special issue focus on the various aspects of intermittency, coherent structures, self-organisation, bifurcation and nonlocality. Given the ubiquity of turbulence, the contributions cover a broad range of systems covering laboratory fluids (channel flow, the Von Kármán flow), plasmas (magnetic fusion), laser cavity, wind turbine, air flow around a high-speed train, solar wind and industrial application.

Recent Advances in Urban Ventilation Assessment and Flow Modelling

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ISBN: 9783038978060 9783038978077 Year: Pages: 448 DOI: 10.3390/books978-3-03897-807-7 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Science (General)
Added to DOAB on : 2019-04-25 16:37:17
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This book contains twenty-one original papers and one review paper published by internationally recognized experts in the Atmosphere Special Issue ""Recent Advances in Urban Ventilation Assessment and Flow Modelling"", years 2017–2019. The Special Issue includes contributions on recent experimental and modelling works, techniques, and developments mainly tailored to the assessment of urban ventilation on flow and pollutant dispersion in cities. The study of ventilation is of critical importance, as it addresses the capacity with which a built urban structure is capable of replacing the polluted air with ambient fresh air. Here, ventilation is recognized as a transport process that improves local microclimate and air quality and closely relates to the term “breathability”. The efficiency with which street canyon ventilation occurs depends on the complex interaction between the atmospheric boundary layer flow and the local urban morphology.The individual contributions to this Issue are summarized and categorized into four broad topics: (1) outdoor ventilation efficiency and application/development of ventilation indices, (2) relationship between indoor and outdoor ventilation, (3) effects of urban morphology and obstacles to ventilation, and (4) ventilation modelling in realistic urban districts. The results and approaches presented and proposed will be of great interest to experimentalists and modelers, and may constitute a starting point for the improvement of numerical simulations of flow and pollutant dispersion in the urban environment, for the development of simulation tools, and for the implementation of mitigation strategies.

Keywords

street canyon --- seasonal variation --- air flow --- pollutant dispersion --- pollutant removal --- natural ventilation --- residential wind environments --- building arrangements --- space pattern --- ventilation efficiency --- CFD simulation --- air change rate (ACH) --- flow and turbulence profiles --- hypothetical urban areas --- street-level ventilation --- ventilation assessment --- wind-tunnel dataset --- street vegetation --- CFD --- aerodynamic and deposition --- tree scenarios --- urban planning --- indoor-outdoor --- mass concentration --- nanoparticles --- particle number concentration (PNC) --- PM10 --- PM2.5 --- sampling --- Total Suspended Particles (TSP) --- ultrafine particles (UFP) --- urban street canyon --- wind enhancement --- architectural intervention --- water channel experiment --- CFD simulation --- passive ventilation --- street canyon --- computational fluid dynamics (CFD) --- ventilation effectiveness --- the age of air --- convective boundary layer --- LES --- street-level ventilation --- small open space --- air change rate per hour (ACH) --- concentration decay method --- urban age of air --- computational fluid dynamic (CFD) simulation --- natural ventilation --- residential building --- climate zone --- thermal comfort --- natural ventilation hour --- Japan cities --- building energy use --- inter-building effect --- highly-reflective building envelope --- BEopt analysis --- source apportionment --- data assimilation --- urban air quality modelling --- wind environment --- Natural Ventilation Potential (NVP) --- PM2.5 --- building–tree grouping patterns --- Computational Fluid Dynamics (CFD) --- LES --- ventilation --- urban planning --- dispersion --- air quality --- street canyon --- traffic tidal flow --- numerical simulation --- vehicular pollution --- non-uniform distribution of the pollution source --- on-road air quality --- traffic composition --- high emitting vehicles --- street canyon --- mobile laboratory --- CFD model --- heat loss --- optimisation --- residential building --- air quality --- carbon dioxide concentration --- ventilation system --- wind pressure coefficient --- airflow network --- multiple linear regression --- natural ventilation --- urban layout --- surrogate model --- schematic urban environment --- wind tunnel --- LES --- validation --- street canyon --- coherent structures --- road tunnel --- natural ventilation --- wind catcher --- intake fraction --- street canyon --- CFD --- Large Eddy Simulation (LES) --- urban air quality --- pedestrian exposure --- concentration fluctuation --- outdoor ventilation --- urban morphology --- building site coverage --- ventilation efficiency --- n/a

Entropy Applications in Environmental and Water Engineering

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ISBN: 9783038972228 Year: Pages: 512 DOI: 10.3390/books978-3-03897-223-5 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Environmental Engineering --- General and Civil Engineering --- Technology (General)
Added to DOAB on : 2019-03-21 15:50:41
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Entropy theory has wide applications to a range of problems in the fields of environmental and water engineering, including river hydraulic geometry, fluvial hydraulics, water monitoring network design, river flow forecasting, floods and droughts, river network analysis, infiltration, soil moisture, sediment transport, surface water and groundwater quality modeling, ecosystems modeling, water distribution networks, environmental and water resources management, and parameter estimation. Such applications have used several different entropy formulations, such as Shannon, Tsallis, Reacutenyi Burg, Kolmogorov, Kapur, configurational, and relative entropies, which can be derived in time, space, or frequency domains. More recently, entropy-based concepts have been coupled with other theories, including copula and wavelets, to study various issues associated with environmental and water resources systems. Recent studies indicate the enormous scope and potential of entropy theory in advancing research in the fields of environmental and water engineering, including establishing and explaining physical connections between theory and reality. The objective of this Special Issue is to provide a platform for compiling important recent and current research on the applications of entropy theory in environmental and water engineering. The contributions to this Special Issue have addressed many aspects associated with entropy theory applications and have shown the enormous scope and potential of entropy theory in advancing research in the fields of environmental and water engineering.

Keywords

complexity --- streamflow --- water level --- composite multiscale sample entropy --- trend --- Poyang Lake basin --- four-parameter exponential gamma distribution --- principle of maximum entropy --- precipitation frequency analysis --- methods of moments --- maximum likelihood estimation --- flood frequency analysis --- generalized gamma (GG) distribution --- principle of maximum entropy (POME) --- entropy theory --- principle of maximum entropy (POME) --- GB2 distribution --- flood frequency analysis --- non-point source pollution --- ANN --- entropy weighting method --- data-scarce --- multi-events --- spatio-temporal variability --- soil water content --- entropy --- arid region --- joint entropy --- NDVI --- temperature --- precipitation --- groundwater depth --- Hei River basin --- turbulent flow --- canopy flow --- randomness --- coherent structures --- Shannon entropy --- Kolmogorov complexity --- entropy --- information transfer --- optimization --- radar --- rainfall network --- water resource carrying capacity --- forewarning model --- entropy of information --- fuzzy analytic hierarchy process --- projection pursuit --- accelerating genetic algorithm --- entropy production --- conditional entropy production --- stochastic processes --- scaling --- climacogram --- turbulence --- water resources vulnerability --- connection entropy --- changing environment --- set pair analysis --- Anhui Province --- cross-entropy minimization --- land suitability evaluation --- spatial optimization --- monthly streamflow forecasting --- Burg entropy --- configurational entropy --- entropy spectral analysis time series analysis --- entropy --- water monitoring --- network design --- hydrometric network --- information theory --- entropy applications --- hydrological risk analysis --- maximum entropy-copula method --- uncertainty --- Loess Plateau --- entropy --- water engineering --- Tsallis entropy --- principle of maximum entropy --- Lagrangian function --- probability distribution function --- flux concentration relation --- uncertainty --- information --- informational entropy --- variation of information --- continuous probability distribution functions --- confidence intervals --- precipitation --- variability --- marginal entropy --- crop yield --- Hexi corridor --- flow duration curve --- Shannon entropy --- entropy parameter --- modeling --- spatial and dynamics characteristic --- hydrology --- tropical rainfall --- statistical scaling --- Tsallis entropy --- multiplicative cascades --- Beta-Lognormal model --- rainfall forecast --- cross entropy --- ant colony fuzzy clustering --- combined forecast --- information entropy --- mutual information --- kernel density estimation --- ENSO --- nonlinear relation --- scaling laws --- power laws --- water distribution networks --- robustness --- flow entropy --- entropy theory --- frequency analysis --- hydrometeorological extremes --- Bayesian technique --- rainfall --- entropy ensemble filter --- ensemble model simulation criterion --- EEF method --- bootstrap aggregating --- bagging --- bootstrap neural networks --- El Niño --- ENSO --- neural network forecast --- sea surface temperature --- tropical Pacific --- entropy --- cross elasticity --- mean annual runoff --- water resources --- resilience --- quaternary catchment --- complement --- substitute --- entropy theory --- complex systems --- hydraulics --- hydrology --- water engineering --- environmental engineering

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