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Hubert Chanson - One of the best experts on this subject based on the ideXlab platform.
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Environmental Hydraulics for Open Channel Flows
2004Co-Authors: Hubert ChansonAbstract:Environmental Hydraulics is a new text for students and professionals studying advanced topics in river and estuarine systems. The book contains the full range of subjects on Open Channel flows, including mixing and dispersion, Saint-Venant equations method of characteristics and interactions between flowing water and its surrondings (air entrainment, sediment transport). Following the approach of Hubert Chansons highly successful undergraduate textbook Hydraulics of Open Channel Flow, the reader is guided step-by-step from the basic principles to more advanced practical applications. Each section of the book contains many revision exercises, problems and assignments to help the reader test their learning in practical situations. • Complete text on river and estuarine systems in a single volume • Step-by-step guide to practical applications • Many worked examples and exercises.
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2 – Fundamentals of Open Channel flows
Environmental Hydraulics of Open Channel Flows, 2004Co-Authors: Hubert ChansonAbstract:Publisher Summary This chapter discusses the fundamentals of Open Channel flows. Open Channel flow describes the fluid motion in Open Channel. The free surface is at constant atmospheric pressure. The driving force of the fluid motion is a combination of pressure (e.g. beneath a sluice gate) and gravity (e.g. sloping Channel). In an Open Channel, the pressure distribution is always hydrostatic, unless the curvature of the streamlines is important. Furthermore, in fluid mechanics and hydraulics, the basic principles are the equations of continuity or conservation of mass, of momentum or conservation of momentum and conservation of energy. Another equation is the Bernoulli equation which is derived from the differential form of the momentum principle. In this chapter, the simplest form of the fundamental principles is developed: i.e. for steady one-dimensional flows. In addition, the hydraulics of short transitions is developed in the chapter, including the concept of specific energy, critical flow conditions, and the hydraulic jump. For the frictionless flow in a horizontal Channel, the Bernoulli principle implies that the specific energy is constant along the Channel. Considering a short, smooth transition in a non-horizontal Channel, the upstream and downstream total heads are equal, by application of the Bernoulli equation.
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Introduction to Part 1: Introduction to Open Channel Flows
Environmental Hydraulics of Open Channel Flows, 2004Co-Authors: Hubert ChansonAbstract:Introduction to Open Channel Flows (Chapter 1). This introduction chapter briefly reviews the fluid properties and some result for static fluids. Then Open Channel flows are defined.
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Environmental hydraulics of Open Channel flows
2004Co-Authors: Hubert ChansonAbstract:The book is an introduction to the hydraulics of Open Channel flows. The material is designed for undergraduate students in Civil, Environmental and Hydraulic Engineering. It will be assumed that the students have had an introductory course in fluid mechanics and that they are familiar with the basic principles of fluid mechanics : continuity, momentum, energy and Bernoulli principles. The book will first develop the basic principles of fluid mechanics with applications to Open Channels. Open Channel flow calculations are more complicated than pipe flow calculations because the location of the free-surface is often unknown 'a priori' (i.e. beforehand). Later the students are introduced to the basic concepts of sediment transport and hydraulic modelling (physical and numerical models). At the end of the course, the design of hydraulic structures is introduced. The book is designed to bring a basic understanding of the hydraulics of rivers, waterways and man-made canals to the reader (e.g. Fig. P-1). The lecture material is divided into four parts of increasing complexity : - Part I : Introduction to the basic principles. Application of the fundamental fluid mechanics principles to Open Channels. Emphasis on the application of the Bernoulli principle and Momentum equation to Open Channel flows. - Part II : Introduction to sediment transport in Open Channels. Basic definitions followed by simple applications. Occurrence of sediment motion in Open Channels. Calculations of sediment transport rate. Interactions between the sediment motion and the fluid motion. - Part III : Modelling Open Channel flows. Physical modelling of Open Channel flows. Numerical modelling of Open Channel flows. Physical modelling : application of the basic principles of similitude and dimensional analysis to Open Channels. Numerical modelling : numerical integration of the energy equation; one-dimensional flow modelling. - Part IV : Introduction to the design of hydraulic structures for the storage and conveyance of water. Hydraulic design of dams, weirs and spillways. Design of drops and cascades. Hydraulic design of culverts : standard box culverts and minimum energy loss culvert. Basic introduction to professional design of hydraulic structures. Application of the basic principles to real design situations. Analysis of complete systems. Applications, tutorials and exercises are grouped into four categories : applications within the main text to illustrate the basic lecture material, exercises for each chapter within each section, revision exercises using knowledge gained in several chapters within one section, and major assignments (i.e. problems) involving expertise gained in several sections : e.g., typically section I and one or two other sections. In the lecture material, complete and detailed solutions of the applications are given. Numerical solutions of some exercises, revision exercises and problems are available on the Internet (Publisher's site : http://www.bh.com/companions/0340740671/). A suggestion/correction form is placed at the end of the book. Comments, suggestions and critic are welcome and they will be helpful to improve the quality of the book. Readers who find an error or mistake are welcome to record the error on the page and to send a copy to the author. "Errare Humanum Est"
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11 – Unsteady Open Channel flows: 1. Basic equations
Environmental Hydraulics of Open Channel Flows, 2004Co-Authors: Hubert ChansonAbstract:Publisher Summary This chapter elaborates the development of the continuity and momentum equations for one-dimensional unsteady Open Channel flows. In unsteady Open Channel flows, the velocities and water depths change with time and longitudinal position. For one-dimensional applications, the relevant flow parameters (example V and d) are functions of time and longitudinal distance. Analytical solutions of the basic equations are nearly impossible because of their non-linearity, but numerical techniques provide approximate solutions for some specific cases. . The basic one-dimensional unsteady Open Channel flow equations are called the Saint–Venant equations. These equations are based upon a number of key, basic assumptions, such as the flow is one dimensional, the velocity is uniform in a cross-section and the transverse free-surface profile is horizontal and the streamline curvature is very small and the vertical fluid accelerations are negligible. The differential form of the Saint–Venant equations is also elaborated.
Hyeongsik Kang - One of the best experts on this subject based on the ideXlab platform.
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Reynolds Stress Modeling of Turbulent Open-Channel Flows
2009Co-Authors: Sung-uk Choi, Hyeongsik KangAbstract:Preface Introduction Numerical Simulations of Open-Channel Flows Reynolds Stress Model Rectangular Channel Flow Partly-Vegetated Wide Open-Channel Flows Compound Open-Channel Flows Conclusions Index.
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Turbulence Modeling of Solute Transport in Open-Channel Flows Over Submerged Vegetation
Advances in Water Resources and Hydraulic Engineering, 2009Co-Authors: Hyeongsik Kang, Sung-uk ChoiAbstract:A model for numerical simulations of solute transport in vegetated Open-Channel flows is proposed. The Reynolds-Averaged Navier-Stokes model is used for the flow analysis. For the turbulence closure, the Reynolds stress model is used, and the generalized gradient diffusive hypothesis is used to close the Reynolds-averaged advection/diffusion equation. The developed model is applied to an experimental case of solute transport in turbulent Open-Channel flows over submerged vegetation reported by Ghisalberti and Nepf (2005). The simulated distributions of mean concentration along the streamwise direction are compared with measured data, showing a good agreement. In addition, numerical simulations reveal that the pattern of secondary currents in vegetated Open-Channel flows is significantly different from that in plain Open-Channel flows. Using the simulated results, the vertical turbulent Schmidt number for the vegetated Open-Channel flow is estimated and a value of 0.58 is obtained. This value can be compared to 0.47, which was obtained by Ghisalberti and Nepf (2005) using laboratory data.
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Reynolds stress modeling of vegetated Open-Channel flows
Journal of Hydraulic Research, 2004Co-Authors: Sung-uk Choi, Hyeongsik KangAbstract:The Reynolds stress model is applied to Open-Channel flows with vegetation. For the computation of pressure-strain term, the Speziale, Sarkar, and Gatski's model is employed. Mellor and Herring's model and Rotta's model are used for diffusion and dissipation rate of Reynolds stress, respectively. Flow structures of Open-Channels under two vegetative conditions are simulated, namely submerged and emergent plants. Plain Open-Channel flows are also simulated for comparisons. Computed profiles are compared with the results from the κ-e model and the algebraic stress model as well as measured data available in the literature. For the plain Open-Channel flow and the Open-Channel flow with emergent vegetation, the Reynolds stress model is observed to simulate the non-isotropic nature of the flows better than the algebraic stress model and the κ-e model. For the Open-Channel flow with submerged vegetation, it is found that the Reynolds stress model predicts the mean flow and turbulence quantities best compared wi...
Sung-uk Choi - One of the best experts on this subject based on the ideXlab platform.
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Reynolds Stress Modeling of Turbulent Open-Channel Flows
2009Co-Authors: Sung-uk Choi, Hyeongsik KangAbstract:Preface Introduction Numerical Simulations of Open-Channel Flows Reynolds Stress Model Rectangular Channel Flow Partly-Vegetated Wide Open-Channel Flows Compound Open-Channel Flows Conclusions Index.
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Turbulence Modeling of Solute Transport in Open-Channel Flows Over Submerged Vegetation
Advances in Water Resources and Hydraulic Engineering, 2009Co-Authors: Hyeongsik Kang, Sung-uk ChoiAbstract:A model for numerical simulations of solute transport in vegetated Open-Channel flows is proposed. The Reynolds-Averaged Navier-Stokes model is used for the flow analysis. For the turbulence closure, the Reynolds stress model is used, and the generalized gradient diffusive hypothesis is used to close the Reynolds-averaged advection/diffusion equation. The developed model is applied to an experimental case of solute transport in turbulent Open-Channel flows over submerged vegetation reported by Ghisalberti and Nepf (2005). The simulated distributions of mean concentration along the streamwise direction are compared with measured data, showing a good agreement. In addition, numerical simulations reveal that the pattern of secondary currents in vegetated Open-Channel flows is significantly different from that in plain Open-Channel flows. Using the simulated results, the vertical turbulent Schmidt number for the vegetated Open-Channel flow is estimated and a value of 0.58 is obtained. This value can be compared to 0.47, which was obtained by Ghisalberti and Nepf (2005) using laboratory data.
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Reynolds stress modeling of vegetated Open-Channel flows
Journal of Hydraulic Research, 2004Co-Authors: Sung-uk Choi, Hyeongsik KangAbstract:The Reynolds stress model is applied to Open-Channel flows with vegetation. For the computation of pressure-strain term, the Speziale, Sarkar, and Gatski's model is employed. Mellor and Herring's model and Rotta's model are used for diffusion and dissipation rate of Reynolds stress, respectively. Flow structures of Open-Channels under two vegetative conditions are simulated, namely submerged and emergent plants. Plain Open-Channel flows are also simulated for comparisons. Computed profiles are compared with the results from the κ-e model and the algebraic stress model as well as measured data available in the literature. For the plain Open-Channel flow and the Open-Channel flow with emergent vegetation, the Reynolds stress model is observed to simulate the non-isotropic nature of the flows better than the algebraic stress model and the κ-e model. For the Open-Channel flow with submerged vegetation, it is found that the Reynolds stress model predicts the mean flow and turbulence quantities best compared wi...
M. Hanif Chaudhry - One of the best experts on this subject based on the ideXlab platform.
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Transient Open-Channel Flows
Applied Hydraulic Transients, 2014Co-Authors: M. Hanif ChaudhryAbstract:In the previous chapters, we considered transient flows in the closed conduits. In this chapter, we discuss transient flows in Open Channels. A flow having a free surface is considered Open-Channel flow even though the Channel may be closed at the top, e.g., a tunnel flowing partially full. A number of common terms are defined, and the examples of transient flows are presented. The dynamic and continuity equations describing these flows are derived, and a number of methods for their solution are discussed. Details of explicit finite-difference and implicit finite-difference method are then presented. This is followed by a discussion of a number of special topics on Open-Channel transients. The chapter concludes with a case study.
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Open-Channel Flow - Open-Channel Flow
2008Co-Authors: M. Hanif ChaudhryAbstract:Analysis of Open-Channel flow is essential for the planning, design, and operation of water-resource projects. The use of computers and the availability of efficient computational procedures has simplified such analysis, and made it possible to handle increasingly complex systems. In Open-Channel Flow, Second Edition, author Hanif Chaudhry draws upon years of practical experience and incorporates numerous examples and real life applications, to provide the reader with: A strong emphasis on the application of efficient solution techniques, computational procedures, and numerical methods suitable for computer analyses; Complete coverage of steady and unsteady flow techniques; A new chapter on sediment transport and updated chapters on uniform flow and two dimensional flow techniques; New and updated problem sets and exercises, a solutions manual for instructors, and a CD-ROM with short computer programs in FORTRAN that include the input data for sample problems and the associated computer output. Open-Channel Flow, Second Edition is written for students in senior-level undergraduate and graduate courses on steady and unsteady Open-Channel flow and for civil engineers needing up-to-date and relevant information on the latest developments and techniques in the field.
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Open-Channel Flow
2007Co-Authors: M. Hanif ChaudhryAbstract:Analysis of Open-Channel flow is essential for the planning, design, and operation of water-resource projects. The use of computers and the availability of efficient computational procedures has simplified such analysis, and made it possible to handle increasingly complex systems. In Open-Channel Flow, Second Edition, author Hanif Chaudhry draws upon years of practical experience and incorporates numerous examples and real life applications, to provide the reader with: A strong emphasis on the application of efficient solution techniques, computational procedures, and numerical methods suitable for computer analyses; Complete coverage of steady and unsteady flow techniques; A new chapter on sediment transport and updated chapters on uniform flow and two dimensional flow techniques; New and updated problem sets and exercises, a solutions manual for instructors, and a CD-ROM with short computer programs in FORTRAN that include the input data for sample problems and the associated computer output. Open-Channel Flow, Second Edition is written for students in senior-level undergraduate and graduate courses on steady and unsteady Open-Channel flow and for civil engineers needing up-to-date and relevant information on the latest developments and techniques in the field.
Wen-wu Yang - One of the best experts on this subject based on the ideXlab platform.
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A knowledge-based expert system for unsteady Open Channel flow
Engineering Applications of Artificial Intelligence, 1992Co-Authors: Kwok-wing Chau, Wen-wu YangAbstract:Abstract Many engineering applications for flood control, flood prediction, etc. require the solution of the unsteady Open Channel flow equations. However, the mathematical modelling and the numerical simulation techniques of unsteady flow in a natural river network are very complicated, requiring highly specialized knowledge and experience. Hydraulic engineers face many difficulties in the design process, such as how to choose a suitable numerical model, how to determine the parameters, how to simulate the natural river boundary conditions, and so on. Recent developments in artificial intelligence and computational hydraulics have made it possible to develop an expert system on hydrodynamics to assist engineers in analyzing unsteady Open Channel flow in river or tidal networks. This paper describes the problem which arises within the specific field of unsteady Open Channel flow, and presents a knowledge-based expert system built to assist the engineers in their design practices.
