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Dawei Han Concise Hydraulics Download free ebooks at bookboon.com 2 Concise Hydraulics © 2008 Dawei Han & Ventus Publishing ApS ISBN 978-87-7681-396-3 Download free ebooks at bookboon.com 3 Contents Concise Hydraulics Contents Preface 8 1. 1.1 1.2 1.3 Fundamentals Properties of Fluids Flow Description Fundamental Laws of Physics 9 9 10 12 2. 2.1 2.2 2.3 2.4 2.5 Hydrostatics Pressure Manometer Pressure Force on Plane Surface Pressure Force on Curved Surface Flotation 15 15 16 16 18 18 3. 3.1 3.2 Energy Equation Basic Formula Applications 26 26 27 4. 4.1 4.2 Momentum Equation The Principle Applications 32 32 33 Please click the advert The next step for top-performing graduates Masters in Management Designed for high-achieving graduates across all disciplines, London Business School’s Masters in Management provides specific and tangible foundations for a successful career in business. This 12-month, full-time programme is a business qualification with impact. 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For more information visit www.london.edu/mm, email mim@london.edu or give us a call on +44 (0)20 7000 7573. * Figures taken from London Business School’s Masters in Management 2010 employment report Download free ebooks at bookboon.com 4 Contents Concise Hydraulics 5. 5.1 5.2 5.3 5.4 5.5 Pipe Flow Introduction Energy losses in pipe flow Local losses (or Minor losses) Grade Line Combination of pipes 41 41 42 45 45 45 6. 6.1 6.2 6.3 6.4 Physical Modelling Background Dimensional Analysis Analysis of Experimental Data Model and Similarity 52 52 52 55 57 7. 7.1 7.2 7.3 Open Channel Flow What is “Open Channel Flow” Channel Geometric Properties Calculation of Hydraulic Radius and Hydraulic Mean Depth 62 62 64 66 8. 8.1 8.2 8.3 8.4 Uniform Flow Introduction Laminar or Turbulent Flow Energy Loss Equations Computation of Uniform Flow 73 73 73 74 76 9. 9.1 9.2 9.3 Channel Design Channel Design Compound Channel The Best Hydraulic Section 83 83 84 87 Please click the advert Teach with the Best. 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See what Agilent can do for you. www.agilent.com/find/EDUstudents www.agilent.com/find/EDUeducators © Agilent Technologies, Inc. 2012 u.s. 1-800-829-4444 canada: 1-877-894-4414 Download free ebooks at bookboon.com 5 Please click the advert Contents 10. 10.1 10.2 10. 3 Critical Flow Small Wave in Open Channel Critical Flow Critical Flow Computation 94 94 94 96 11. 11.1 11.2 11.3 11.4 Rapidly Varied Flow Sudden Transitions Depth of Flow Height of Hump Specific Energy 103 103 103 106 107 12. 12.1 12.2 12.3 12.4 Hydraulic Jump Jump Equation Hydraulic Jump in Rectangular Channel Hydraulic Jump in Trapezoidal Channel Hydraulic jump in Sloping Channel 114 114 116 116 118 13. 13. 1 13.2 13.3 13.4 Hydraulic Structures Flumes (Venturi) Weirs (Broad-crested weir) Energy dissipators Sluice Gates 123 123 125 125 127 14. 14.1 14.2 14.3 14.4 Gradually Varied Flow Equation of Gradually Varied Flow Classification of Surface Profiles Flow Profile Sketch Flow transitions 131 131 133 133 135 You’re full of energy and ideas. And that’s just what we are looking for. © UBS 2010. All rights reserved. Concise Hydraulics Looking for a career where your ideas could really make a difference? UBS’s Graduate Programme and internships are a chance for you to experience for yourself what it’s like to be part of a global team that rewards your input and believes in succeeding together. Wherever you are in your academic career, make your future a part of ours by visiting www.ubs.com/graduates. www.ubs.com/graduates Download free ebooks at bookboon.com 6 Concise Hydraulics Contents 15. 15.1 15.2 15.3 15.4 Computation of Flow Profile Introduction Numerical integration methods Computation Procedure through an Example Further Computational Information 139 139 140 140 142 16. 16.1 16.2 16.3 16.4 Unsteady Flow Basic Types 1 Rapidly Varied Unsteady Flow Gradually Varied Unsteady Flows (Saint-Venant equations) Software packages 148 148 148 150 154 17. 17.1 17.2 17.3 Hydraulic Machinery Hydropower and Pumping Station Turbines Pump and Pipeline 159 159 161 165 Appendix: Further Reading Resources 177 360° thinking Please click the advert . 360° thinking . 360° thinking . Discover the truth at www.deloitte.ca/careers © Deloitte & Touche LLP and affiliated entities. Discover the truth at www.deloitte.ca/careers © Deloitte & Touche LLP and affiliated entities. Download free ebooks at bookboon.com Discover the truth7at www.deloitte.ca/careers © Deloitte & Touche LLP and affiliated entities. © Deloitte & Touche LLP and affiliated entities. D Concise Hydraulics Preface Preface Hydraulics is a branch of scientific and engineering discipline that deals with the mechanical properties of fluids, mainly water. It is widely applied in many civil and environmental engineering systems (water resources management, flood defence, harbour and port, bridge, building, environment protection, hydropower, irrigation, ecosystem, etc). This is an introductory book on hydraulics and written for undergraduate students in civil and environmental engineering, environmental science and geography. The aim of this book is to provide a concise and comprehensive coverage of hydraulics that is easy to access through the Internet. The book content covers the fundamental theories (continuity, energy and momentum equations), hydrostatics, pipe flow, physical modelling (dimensional analysis and similarity), open channel flow, uniform flow, channel design, critical flow, rapidly varied flow, hydraulic jump, hydraulic structures, gradually varied flow, computation of flow profile, unsteady flow and hydraulic machinery (pump and turbine). The text has been written in a concise format that is integrated with the relevant graphics. There are many examples to further explain the theories introduced. The questions at the end of each chapter are accompanied by the corresponding answers and full solutions. A list of recommended reading resources is provided in the appendix for readers to further explore the interested hydraulics topics. Due to its online format, it is expected that the book will be updated regularly. If you find any errors and inaccuracies in the book, you are encouraged to email me with feedback and suggestions for further improvements. Dawei Han Reader in Civil and Environmental Engineering, Water and Environmental Management Research Centre Department of Civil Engineering University of Bristol, BS8 1TR, UK E-mail: d.han@bristol.ac.uk http://www.bris.ac.uk/civilengineering/person/d.han.html August 2008 Download free ebooks at bookboon.com 8 Concise Hydraulics Fundamentals 1. Fundamentals Hydraulics is a branch of scientific and engineering discipline that deals with the mechanical properties of fluids, mainly water. It is widely applied in water resources, harbour and port, bridge, building, environment, hydropower, pumps, turbines, etc. 1.1 Properties of Fluids 1) Density: Mass per unit volume U (kg/m3) For water, U = 1000kg/m3 at 4°C, U = 998 kg/m3 at 20°C 3 at 20°C at standard pressure For air, U = 1.2kg/m 2) Specific gravity: Ratio of the substance’s density and water’s density at 4oC 3) Pressure: Normal fluid force divided by area over which it acts (N/m2). (Note: pressure is scalar while force is a vector. A force is generated by the action of pressure on a surface and its direction is given by the surface orientation) 4) Viscosity and shear stress Take an element from the fluid Moving with U u+du d dy Stationary W P u du dy and the total force F WA P UA d where P absolute viscosity (N s/m2) , W shear stress (N/m2). Fluids that follow the aforementioned formulas are called Newtonian fluids. Download free ebooks at bookboon.com 9 Concise Hydraulics Examples Air Water Engine oil SAE30W Fundamentals P =1.79 x 10-5 Ns/m2 P = 1.137x10-3 Ns/m2 P =0.44 Ns/m2 High viscosity: sticky fluid; low viscosity: slippy fluid P is not a constant and changes with temperature. Another form of viscosity is kinematic viscosity Q P (m2/s) U Assumptions for the equation: 1) Fluids are Newtonian fluids (Non-Newtonian fluids are studied by Rheology, the science of deformation and flow); 2) The continuum approximation: the properties of the fluid can be represented by continuous fields representing averages over many molecules (The exception is when we are dealing with gases at low pressures). 1.2 Flow Description There are two approaches 1) Lagrangian approach: follow individual fluid element as it moves about; 2) Eulerian approach: focus on a fixed location and consider how the fluid properties change at that location as time goes on. Definitions relating to Fluids in Motion Ideal flow: frictionless and incompressible (i.e. nonviscous). Steady flow: The flow is steady if the properties at each point in the fluid do not change with time. One, Two and 3D flows: One dimensional flow requires only one coordinate to describe the change in flow properties. Two dimensional flow requires two coordinates to describe the change in flow properties. Three dimensional flow requires all three coordinates to describe the change in flow properties. In general, most flow fields are three dimensional. However, many practical problems can be simplified into one or two dimensions for computational convenience. Download free ebooks at bookboon.com 10