GATE Water Resource Engineering Book

WATER RESOURCE ENGINEERING

for

Civil Engineering By

www.thegateacademy.com

Syllabus

Water Resource Engg

Syllabus for Water Resource Engineering Fluid Mechanics and Hydraulics Properties of fluids, principle of conservation of mass, momentum, energy and corresponding equations, potential flow, applications of momentum and Bernoulli's equation, laminar and turbulent flow, flow in pipes, pipe networks. Concept of boundary layer and its growth. Uniform flow, critical flow and gradually varied flow in channels, specific energy concept, hydraulic jump. Forces on immersed bodies, flow measurements in channels, tanks and pipes. Dimensional analysis and hydraulic modeling. Kinematics of flow, velocity triangles and specific speed of pumps and turbines. Hydrology Hydrologic cycle, rainfall, evaporation, infiltration, stage discharge relationships, unit hydrographs, flood estimation, reservoir capacity, reservoir and channel routing. Well hydraulics. Irrigation Duty, delta, estimation of evapo-transpiration. Crop water requirements. Design of: lined and unlined canals, waterways, head works, gravity dams and spillways. Design of weirs on permeable foundation. Types of irrigation system, irrigation methods. Water logging and drainage, sodic soils.

Analysis of GATE Papers (Water Resource Engineering) Year

Percentage of marks

2013

15.00

2012

14.00

2011

14.00

2010

12.00

2009

14.00

2008

19.33

2007

20.67

2006

21.33

2005

24.66

2004

31.33

2003

22.60

Overall Percentage

18.99%

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Contents

Water Resource Engg

CONTENTS

#1.

Chapter Introduction        

#2.

Pressure and It’s Measurement       

#3.

Parallel Axis Theorem Force on a Vertical Plane Area Summary of Main Points Solved Examples Assignment Answer Keys Explanations

Floatation and Stability    

#5.

Tensors Measurement of Pressure Summary of Main Points Solved Examples Assignment Answer Keys Explanations

Hydrostatic Forces on Plane Surfaces       

#4.

Branches of Fluid Mechanics Compressible and Incompressible Fluids Moving and Stationary Parallel Plates Summary of Main Points Solved Examples Assignment Answer Keys Explanations

Hydrostatic Terminology Stability Summary of Main Points Solved Examples

Relative Equilibrium of Fluids    

Liquid Mass Subjected to Uniform Linear Horizontal Acceleration Acceleration of a Fluid Mass Along a Slope Free Vortex Summary of Main Points

Page No 1–12 1– 3 3 4–7 7–8 9 – 10 11 12 12

13 – 22 13 – 15 15 16 – 17 18 – 20 21 22 22

23–35 23 – 24 24 – 26 26 – 27 28 – 32 33 – 34 35 35

36 – 44 36 – 38 38 – 40 41 – 42 42 – 44

45 – 55 45 – 46 47 – 51 51 – 52 52 – 53

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Contents   

#6.

Equation of Motion and Energy Equation The Venturimeter The Orifice Plate Summary of Main Points Solved Examples Assignment Answer Keys Explanations

Flow Through Pipes    

#9.

Kinematics Compressible Flow & Incompressible Flow Flow Visualization Flow Net Theory Summary of Main Points Solved Examples Assignment Answer Keys Explanations

Fluid Dynamics        

#8.

Assignment Answer Keys Explanations

Kinematics of Flow         

#7.

Water Resource Engg

Major Losses Applying Bernoulli’s Equation Hydraulic Gradient and Total Energy Line Summary of Main Points

Impulse Momentum Equation and Its Application   

The Momentum Equation Free Liquid Jets Summary of Main Points

#10. Flow Through Orifices and Mouth Pieces       

Sharp Edged Orifice Discharging Free Jet Experimental Determination of the Coefficients for an Orifice Flow Through Submerged (or drowned) Orifice Summary of Main Points Assignment Answer Keys Explanations

54 55 55

56 – 72 56 – 57 57 – 58 58 – 63 63 64 – 67 67 – 70 71 72 72

73–89 73 – 75 75 – 76 76 – 79 80 – 83 83 – 87 88 89 89

90 – 100 90 – 91 91 – 93 93 – 95 96 – 100

101–105 101 –102 103 104 – 105

106–122 106 – 108 108 – 112 113 114 – 117 118 – 120 121 121 – 122

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Contents

Water Resource Engg

#11. Weirs and Notches      

Weirs and Notches Flow over a Trapezoidal Weirs or Notch Summary of Main Points Assignment Answer Keys Explanations

#12. Boundary Layer Flow       

Boundary Layer Flow Boundary Conditions for Velocity Profiles Turbulent Boundary Layer Summary of Main Points Assignment Answer Keys Explanations

#13. Viscous Flow    

Flow of Viscous Fluid Through Circular Pipe Flow of Viscous Fluid Between Two Parallel Plates Methods of Determination of Co – Efficient of Viscosity Summary of Main Points

123–132 123 – 125 125 – 126 126 – 130 131 132 132

133 – 142 133 –135 135 – 136 136 – 137 138 – 140 141 142 142

143–159 143 – 145 146 – 151 151 – 152 152 – 159

#14. Hydraulics & Hydraulic Machinery

160 – 200

Flow in Open Channels Measuring Flumes Bresse’s Method Curved Vanes on Wheel Reciprocating Pumps Summary of Main Points

160 – 165 165 – 168 168 – 173 173 – 187 187 –188 189 – 200

     

#15. Dimensional Analysis   

Dimensional Analysis Model Laws or Similarity Law Summary of Main Points

#16. Irrigation       

Introduction Flow Irrigation Limitations Solved Examples Assignment Answer Keys Explanations

201 – 208 201 – 203 203 – 206 206 – 208

209 – 216 209 – 210 210 – 213 213 214 215 216 216

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Contents

Water Resource Engg

#17. Water Requirements of Crops   

Definition Duty at Various Places Optimum Utilization of Irrigation Water

#18. Soil Moisture Irrigation Relationship  

Field Capacity Solved Examples

#19. Sediment Transport and Design of Irrigation Channels          

Sediment Transport and Design of Irrigation Channels Mechanics of Sediment Transport Water Logging Control Suitability Design of Channels Economical & Physical Justification for Canal Causes of Failure of Weir on Permeable Foundation Assignment Answer Keys Explanations

#20. Hydrology          

Introduction to Hydrology Precipitation Evaporation and Infiltration Stage Discharge Relationships hydrograph and Runoff Floods Estimation Well Hydraulics Assignment Answer Keys Explanations

Module Test   

Test Questions Answer Keys Explanations

Reference Books

217–221 217 – 218 218 – 220 220 – 221

222–228 222 – 223 224 – 228

229–266 229 – 230 231 – 234 234 – 237 237 238 – 248 249 – 250 250 – 263 264 – 265 266 266

267 - 326 267 – 271 271 – 281 281 – 295 295 – 300 301 – 310 310 – 314 314 – 320 321 – 324 325 325 – 326

327 - 335 327 – 333 334 334 – 335

336

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Chapter 1

Water Resource Engg

Chapter-1 Introduction Branches of Fluid Mechanics 1. Fluid statics:- deals with fluid at rest 2. Fluid kinematics:- deals with velocities & streamlines 3. Fluid dynamics:- That deals with velocity & accelerations and hence with forces.

Classical Hydrodynamics:- It is mathematical subject that deals with ideal frictionless fluids. Classical Hydraulics:- Deals with Reals fluid. Fluid Mechanics = Classical Hydrodynamics + Classical Hydraulics. Common Temperature Scales 1.

=

2.

273



C

For most gases the molecular density is 2.7 x 1025 molecules per m3.

Continuum Flow Two factors which are important in determining the validity of continuum model. 1. The distance between molecules. This distance is evidently not the same for all the molecules in the gas at anyone time. Therefore an average distance called the molecular mean free path. The mean free path of atmospheric air is 50 – 70 mm. 2. Elapsed time between collisions. 

A dimensionless parameter, the Knudsen number Kn = = Molecular mean free path. L = Characteristics length.

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Chapter 1

Water Resource Engg

1) Continuum ( n ≤ 0.01) – no slip condition. It is condition of zero velocity at solid boundary. 2) Slip flow (0.01 < Kn ≤ 0.1) – These conditions provide for a finite velocity and a temperature jump at a solid boundary. 3) Transition flow (0.10 < n ≤ 10) – The kinetic theory of gases must be employed to adequately describes this flow. 4) Free molecular flow (Kn > 10) molecular interaction can be neglected. 

Homogeneity – Identical in all points. Isotropy – Identical in all directions. 1. Stress Fixed deformation

Solid

2. Stress continuous deformation

Solid

Terms a. Density (ρ) =

=

Unit (Kg/m3, slug/ft3). b. Specific weight (γ). γ γ

1 ⁄ units ( ⁄ m ft

pcf).

eg

c. Specific volume ∀ ∀

unit (m ⁄ g ft ⁄slug).

d. Specific gravity (S) THE GATE ACADEMY PVT.LTD. H.O.: #74, Keshava Krupa (third Floor), 30th Cross, 10th Main, Jayanagar 4th Block, Bangalore-11 : 080-65700750,  [email protected] © Copyright reserved. Web: www.thegateacademy.com Page 2

Chapter 1

Water Resource Engg

S= It is the ratio of specific weight (or density) of a fluid at actual conditions to the specific weight (or density) of pure water at standard conditions (101 kN/m2, 200C). 

Specific weight Of liquids. 1. Varies only slightly with pressure. 2. May vary considerably with temperature.

Compressible and Incompressible Fluids Compressible – Variable density. Incompressible – Constant density. Ideal Fluids 1. No friction 2. Inviscid (zero viscosity) fluid. 3. Internal forces at any section within are normal (pressure forces). 4. Ideal fluid & ideal gas or perfect gas both are different. Real Fluids 1. Tangential or shearing forces always develop where there is motion relative to solid body. Thus, fluid friction is created. 2. Shear forces opposes motion of one particle past another. 3. Friction forces gives rise to a fluid property called viscosity. Variation of Viscosity with Temperature Liquids:- Viscosity decreases as temperature increases. Gases:- Viscosity increases as temperature increases Liquids

Gases

Viscosity

Temperature

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Chapter 1

Water Resource Engg

Moving and Stationary Parallel Plates (2)

Moving plate F, U

y

(1) V

u →du

Stationary plate

Fluid particles adhere to walls: No slip conditions Velocity: zero at (1) & U at (2) → velocity profile. For small U γ and no net flow → linear velocity experiment show that F ~ ow newton’s eqn. τ( τ

)∝ μ

μ

here μ

coefficient of viscosity a solute viscosity dynamic viscosity or simply viscosity.

Pseudo plastic

Shear stress yield stress

Dilatant 1

μ Ideal fluid du dy (Velocity gradient) ∴ Rheological diagram

Based on Property of Viscosity, Fluids May Be Classified (i)

Ideal Fluid  μ

0

o shear stress exists.

(ii) Real Fluid – Shear stresses are induced when fluid is in motion, which possesses viscosity. (iii) Newtonian Fluid:- which follows the Newton law (τ ∝

). Eg. Air, water.

(iv) Non Newtonian Fluids:- It is a fluid in which shear stress is not proportional to velocity gradient Ex:- paints printer’s ink gel emulsions. THE GATE ACADEMY PVT.LTD. H.O.: #74, Keshava Krupa (third Floor), 30th Cross, 10th Main, Jayanagar 4th Block, Bangalore-11 : 080-65700750,  [email protected] © Copyright reserved. Web: www.thegateacademy.com Page 4