# Open Channel Flow

In Open Channel Flow, we studied a total of six chapters, which are as follows:

**Chapter 1:**Open Channel Flow – Introduction**Chapter 2:**Uniform Flow**Chapter 3:**Energy-Depth Relationship**Chapter 4:**Gradually Varied Flow**Chapter 5:**Rapidly Varied Flow: Hydraulic Jump**Chapter 6:**Unsteady Flow: Surge

## Open Channel Flow – Introduction: 1

**Open Channel Flow**, Difference Between Open Channel Flow and Pipe Flow, **Type of Force In Open Channel Flow**– Inertia Force, Gravity Force, Viscous Force. Reynold’s Number, Froude Number.

**Different Types Of Open Channel:** **1. **On The Basis of Formation– Natural Channel, Artificial Channel. **2. **On The Basis Of Change In Properties Of Channel- Prismatic Channel, Non-Prismatic Channel. **3.** On The Basis Of Type Of Boundary– Rigid Boundary Channel, Mobile Boundary Channel

**Types of Open Channel Flow- **Steady & Unsteady Flows, Uniform and Non-Uniform Flows, Varied Flow- A. Gradually Varied Flow, B. Rapidly Varied Flow, C. Spatially Varied Flow

**Types of Non-uniform flows Or Varied Flow-** Gradually varied steady flow: Backing up of water in a stream due to dam, Gradually varied unsteady flow: Passage of flood wave in a river, Rapidly varied steady flow: A hydraulic jump below a spillway or a sluice gate, Rapidly varied unsteady flow: A surge moving up a canal breaking of wave on the shore, Spatially varied steady flow: Flow over side weir or flow over bottom rock, Spatially varied unsteady flow: Surface runoff due to heavy rainfall. Different Combination Of Flow

**Laminar and Turbulent flow- **Laminar Flow, Turbulent Flow. **Critical Flow, Subcritical Flow & Supercritical Flow, **Celerity (Co), **Geometric Element Of Channel Section- **Depth of Flow (y), Depth of Flow Section (d), Top Width (T), Wetted/ Water Area (A), Wetted Perimeter (P), Hydraulic Radius/ Hydraulic Mean Depth of Flow (R), Hydraulic Depth.

Velocity Distribution In Open Channel Flow, Kinetic energy correction factor (α), Momentum correction factor (β), **Pressure Distribution- **Case (i) Channel With Small Slope, Case (ii) Channel With Large Slope

**Different Equation Used In OCF – ****1**. Continuity Equation –(A). Continuity Equation For Steady Flow (Uniform Flow, GVF, RVF), (B). Continuity Equation For Steady Flow (SVF), (C). Continuity Equation For Unsteady Flow (GVF, RVF). **2**. Energy Equation, **3**. Momentum Equation In Open Channel Flow- For Steady Flow, For Unsteady Flow, **SPECIFIC FORCE.**

## Uniform Flow: 2

**Uniform Flow, **Analysis of Uniform Flow, **Chezy Equation- **Derivation From Darcy’s Weisbach Equation. **Manning’s Equation,** Relationship Between Chezy’s Constant & Friction Factor, Momentum Equation of Uniform Flow, **Most Economical Or Most Efficient Section of Channel, **

**Relationship Between Various Element To From An Efficient Channel Section- **1. Most Efficient Rectangular Section, 2. Most Efficient Triangular Section, 3. Most Efficient Trapezoidal Section– Case I: When side slope is fixed, Case II: When side slope is varied. 4. Most Efficient Circular Section- From Manning’s Equation, From Chezy’s Equation

**Properties of Most Efficient Channel Section of Different Shapes, ****Type of Channel According to Efficiency – **Type.1, Type.2.

**Shear Stress On The Boundary Of Uniform Flow In Open Channel Flow **

## Energy- Depth Relationship: 3

**Specific Energy**, **Relationship Between Specific Energy and Depth of Flow- **Case.1 When Discharge is Constant, Case.2 When Discharge is Variable.

**Calculation of the Critical Depth-** Critical Depth of Rectangular Section, Critical Depth of Triangular Section, Section Factor Z, Relation Between Discharge & Depth of Flow

**Channel Transition- ****Channel with a Hump (Flow Transition Due to Hump Creations)- **1. Subcritical Flow, 2. Super Critical Flow, Size of Maximum Hump For Critical Flow, Energy Loss due to Hump, **Transition With Reduction of Width in a Rectangular Channel (Flow Transition Due to Width Contraction)- **1. Subcritical Flow, 2. Supercritical Flow

## Gradually Varied Flow: 4

**Gradually Varied Flow, **Assumption In GVF,** Differential Equation of GVF,** Differential Energy Equation, **Classification Of Flow Profiles- **The slope of the channel can be classified as, Following Point Must Be Noted Before Studding the Characteristic of Flow Profile, Important Point.

**Practical Cases of GVF Profile- **(A) Type-M Profiles: M1 Profile, M2 Profile, M3 Profile. (B) Type-S Profiles: S1 Profile, S2 Profile, S3 Profile, (C) Type-C Profiles, (D) Type-H Profiles, (E) Type-A Profiles.

**Control Section, **Break In Grade, **Gradually Varied Flow Computation**–Direct Step Method, **Procedure For Computation of GVF Profiles **

## Rapidly Varied Flow: Hydraulic Jump: 5

**Rapidly Varied Flow, ****Hydraulic Jump**– Applications of Hydraulic Jump, Analysis of Hydraulic Jump. Momentum Equation for the Hydraulic Jump, **Hydraulic Jump in A Horizontal Rectangular Channel- **(A) Sequent Depth Ratio, (B) Energy Loss, (C) Relative Energy Loss, (D) Efficiency of Jump, (E) Height of Jump, (F) Length of Jump

**Classification of Jumps- **(i) Undular Jump (1.0 < F1 ≤ 1.7), (ii) Weak Jump (1.7 < F1 ≤ 2.5), (iii) Oscillating Jump (2.5 < F1 ≤ 4.5), (iv) Steady Jump (4.5 < F1 ≤ 9.0), (v) Strong or Choppy Jump (F1>9.0).

Velocity Profile For Hydraulic Jump, Jumps in Horizontal Non-rectangular Channels, Jumps on a Sloping Floor, Energy Dissipation, Location Of Jump

## Unsteady Flow: Surge: 6

**Introduction of Unsteady Flow**, Surges in Open Channel, **Type Of Surges- **(A) Positive Surge Moving Downstream, (B) Positive Surge Moving Upstream, (C) Negative Surge Moving Downstream, (D) Negative Surge Moving Upstream. **Analysis of Surges- **Case A- Positive Surge Moving Downstream Due to Sudden Open Sluice Gate, Case B- Positive Surge Moving Upstream Due to Sudden Closed Sluice Gate, **Celerity.**

## Topics

The gradually varied flow (GVF) is defined as steady non- uniform flow, where the depth of flow varies gradually from section to section along the length of channel. (A steady non-uniform flow in a prismatic channel with gradual changes in its water surface elevation is termed as gradually varied flow (GVF).

Open channel flow refers to the flow of liquid in channel open to atmosphere or in partially filled conduit (Pipe). Example- River, Flood, Rivulets, Torrent, Sewers carrying sewage, Rode side Gutter. Detailed discuss about OCF.