Civil Engineering : Water resource engineering, THE GATE ACADEMY

WATER RESOURCE ENGINEERING

ffoorr

Civil Engineering

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Syllabus Water Resource Engg

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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 Overall Percentage

2013 15.00

18.99%

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

Contents Water Resource Engg

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C O N T E N T S

Chapter Page No

#1. Introduction 1–12

Branches of Fluid Mechanics 1– 3 Compressible and Incompressible Fluids 3 Moving and Stationary Parallel Plates 4 – 7 Summary of Main Points 7 – 8 Solved Examples 9 – 10 Assignment 11 Answer Keys 12 Explanations 12

#2. Pressure and It’s Measurement 13 – 22 Tensors 13 – 15 Measurement of Pressure 15 Summary of Main Points 16 – 17 Solved Examples 18 – 20 Assignment 21 Answer Keys 22 Explanations 22

#3. Hydrostatic Forces on Plane Surfaces 23–35 Parallel Axis Theorem 23 – 24 Force on a Vertical Plane Area 24 – 26 Summary of Main Points 26 – 27 Solved Examples 28 – 32 Assignment 33 – 34 Answer Keys 35 Explanations 35

#4. Floatation and Stability 36 – 44 Hydrostatic Terminology 36 – 38 Stability 38 – 40 Summary of Main Points 41 – 42 Solved Examples 42 – 44

#5. Relative Equilibrium of Fluids 45 – 55 Liquid Mass Subjected to Uniform Linear Horizontal

Acceleration 45 – 46

Acceleration of a Fluid Mass Along a Slope 47 – 51 Free Vortex 51 – 52 Summary of Main Points 52 – 53


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Assignment 54 Answer Keys 55 Explanations 55

#6. Kinematics of Flow 56 – 72 Kinematics 56 – 57 Compressible Flow & Incompressible Flow 57 – 58 Flow Visualization 58 – 63 Flow Net Theory 63 Summary of Main Points 64 – 67 Solved Examples 67 – 70 Assignment 71 Answer Keys 72 Explanations 72

#7. Fluid Dynamics 73–89 Equation of Motion and Energy Equation 73 – 75 The Venturimeter 75 – 76 The Orifice Plate 76 – 79 Summary of Main Points 80 – 83 Solved Examples 83 – 87 Assignment 88 Answer Keys 89 Explanations 89

#8. Flow Through Pipes 90 – 100 Major Losses 90 – 91 Applying Bernoulli’s Equation 91 – 93 Hydraulic Gradient and Total Energy Line 93 – 95 Summary of Main Points 96 – 100

#9. Impulse Momentum Equation and Its Application 101–105 The Momentum Equation 101 –102 Free Liquid Jets 103 Summary of Main Points 104 – 105

#10. Flow Through Orifices and Mouth Pieces 106–122 Sharp Edged Orifice Discharging Free Jet 106 – 108 Experimental Determination of the Coefficients for an Orifice 108 – 112 Flow Through Submerged (or drowned) Orifice 113 Summary of Main Points 114 – 117 Assignment 118 – 120 Answer Keys 121 Explanations 121 – 122


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#11. Weirs and Notches 123–132 Weirs and Notches 123 – 125 Flow over a Trapezoidal Weirs or Notch 125 – 126 Summary of Main Points 126 – 130 Assignment 131 Answer Keys 132 Explanations 132

#12. Boundary Layer Flow 133 – 142 Boundary Layer Flow 133 –135 Boundary Conditions for Velocity Profiles 135 – 136 Turbulent Boundary Layer 136 – 137 Summary of Main Points 138 – 140 Assignment 141 Answer Keys 142 Explanations 142

#13. Viscous Flow 143–159 Flow of Viscous Fluid Through Circular Pipe 143 – 145 Flow of Viscous Fluid Between Two Parallel Plates 146 – 151 Methods of Determination of Co – Efficient of Viscosity 151 – 152 Summary of Main Points 152 – 159

#14. Hydraulics & Hydraulic Machinery 160 – 200 Flow in Open Channels 160 – 165 Measuring Flumes 165 – 168 Bresse’s Method 168 – 173 Curved Vanes on Wheel 173 – 187 Reciprocating Pumps 187 –188 Summary of Main Points 189 – 200

#15. Dimensional Analysis 201 – 208 Dimensional Analysis 201 – 203 Model Laws or Similarity Law 203 – 206 Summary of Main Points 206 – 208

#16. Irrigation 209 – 216 Introduction 209 – 210 Flow Irrigation 210 – 213 Limitations 213 Solved Examples 214 Assignment 215 Answer Keys 216 Explanations 216


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#17. Water Requirements of Crops 217–221 Definition 217 – 218 Duty at Various Places 218 – 220 Optimum Utilization of Irrigation Water 220 – 221

#18. Soil Moisture Irrigation Relationship 222–228 Field Capacity 222 – 223 Solved Examples 224 – 228

#19. Sediment Transport and Design of Irrigation Channels 229–266 Sediment Transport and Design of Irrigation Channels 229 – 230 Mechanics of Sediment Transport 231 – 234 Water Logging Control 234 – 237 Suitability 237 Design of Channels 238 – 248 Economical & Physical Justification for Canal 249 – 250 Causes of Failure of Weir on Permeable Foundation 250 – 263 Assignment 264 – 265 Answer Keys 266 Explanations 266

#20. Hydrology 267 - 326 Introduction to Hydrology 267 – 271 Precipitation 271 – 281 Evaporation and Infiltration 281 – 295 Stage Discharge Relationships 295 – 300 hydrograph and Runoff 301 – 310 Floods Estimation 310 – 314 Well Hydraulics 314 – 320 Assignment 321 – 324 Answer Keys 325 Explanations 325 – 326

Module Test 327 - 335 Test Questions 327 – 333 Answer Keys 334 Explanations 334 – 335

Reference Books 336

Chapter 1 Water Resource Engg

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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.



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.

2.

Terms

a. Density (ρ) =

=

Unit (Kg/m3, slug/ft3).

b. Specific weight (γ).

γ

units (

m ⁄ 1 ft ⁄ pcf).

γ eg

c. Specific volume ∀

∀

unit (m

g⁄ ft

slug⁄ ).

d. Specific gravity (S)

Solid

Stress

continuous deformation

Solid

Stress

Fixed deformation



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

Temperature

Viscosity

Liquids Gases



Moving and Stationary Parallel Plates

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.

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.

Ideal fluid

Shear stress

Pseudo plastic

Dilatant

(Velocity gradient) du

dy

μ 1

yield stress

∴ Rheological diagram

Moving plate F, U (2)

y

(1) Stationary plate V u →du

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Civil Engineering : Water resource engineering, THE GATE ACADEMY