1. LECTURER: MADAM NOR AMANI FILZAH MOHD KAMIL
HYDRAULICS (BFC 21103)
LECTURER: MADAM NOR AMANI FILZAH MOHD KAMIL
ROOM: ST LEVEL 3, ROOM-PM 4

2. Learning Objectives
Knowing open stream classification and properties of fluid.
Understanding the nature of the flow in an open channel.
Understanding the definition of geometric elements in the calculation of open channel flow.

3. Learning Outcomes
Making a comparison between open channel flow and flow in a pipe.
Define and describe the types of flow.
State flow conditions and flow regimes.

4. Syllabus 1.1 Introduction (slide 5) 1.2 State of Flow (slide 17)
1.3 Types of Open Channel Flow (slide 22)
1.4 Geometric Element of Open Channel (slide 31)

5. What is the significant of this subject to civil engineer?
Introduction
Hydraulic is related to the principle of fluid mechanics usage for structure of water engineering, civil and environmental engineering necessity especially hydraulic structure example channel, river, weir and water treatment plant
What is the significant of this subject to civil engineer?

6. Introduction Properties of Fluid Detailed in fluid mechanics
Relative Density
Compressibility
Capillarity
Specific Gravity
Density
Bulk Modulus
Viscosity
Detailed in fluid mechanics

7. Introduction Open Channel Flow
Flow in open channel has a free surface which is caused by atmosphere pressure
Atmosphere Free surface
Flow d
Distributed flow Zo
Datum

8. Introduction
Open Channel Flow

9. Example: Constant flow in piping flow in time
Steady Flow
Flow in an open-channel is considered steady if the depth of flow (y) does not change and assumed to be constant during the time interval; dy / dt = 0.
Example: Constant flow in piping flow in time

10. Steady Flow (Example)

11. Unsteady Flow
Flow in an open-channel is considered unsteady if the water surface and depth of flow fluctuate from time to time. This means, dy / dt  0.
Unsteady uniform flow is an impossible condition
Example: flood

12. Uniform and Non-uniform Flow
Flow is considered uniform if the depth of flow is the same at every section of the flow (dy/dx = 0). While, flow is considered non-uniform flow if the depth of flow varies at different sections of the flow (dy/dx  0).
Non-uniform flow
Uniform flow

13. Uniform and Non-uniform Flow
Gradually varied flow (GVF) the depth changes gradually over a long distance along the length of a channel.
Rapidly varied flow (RVF) the depth changes abruptly over a comparative short distance

14. Gradually varied flow (GVF)
Example: backwater at the upstream of weir or sluice gate.

15. Rapidly varied flow (RVF)
Example: hydraulic jump

16. Summary Open Channel Flow Steady Flow Uniform Flow Non-uniform GVF RVF
Unsteady Flow
GVUF
RVUF

17. State of Flow
Viscosity effect
Gravity effect

18. Viscosity Effect Reynolds number depends on viscosity
Fluid viscosity is constant
Re < laminar
500 < Re < transition
Re > turbulent

19. Laminar and Turbulent Flow
Laminar flow
Low velocity in small cross section channel.
High viscosity.
Turbulent Flow
Deep of flow.
Non-prismatic cross section (i.e; river) create the turbulent flow.
Transition
State of flow happen when laminar flow change to turbulent flow before alter to fully turbulent.

20. REYNOLDS EXPERIMENT Result
Osborne Reynolds was the
first scientist who had distinguished
the type of flow by using a
simple apparatus in 1883.

21. Gravity Effect
State as inertia force to gravity force ratio and known as Froude number,
Where;
Fr = 1 – critical
Fr < 1 – sub critical
Fr > 1 – super critical

22. Sub critical laminar – Fr < 1.0, Re < 500
Flow Regime
Combination of viscosity and gravity effect will create 4 state of regime which are;
Sub critical laminar – Fr < 1.0, Re < 500
Super critical laminar – Fr > 1.0, Re < 500
Sub critical turbulent – Fr < 1.0, Re > 12500
Super critical turbulent – Fr > 1.0, Re > 12500

23. Type of Open Channel
Natural channel
Artificial channel

24. Natural channels are waterways that exist naturally on earth.
Type of Open Channel
Natural Channel
Natural channels are waterways that exist naturally on earth.
The properties of natural channels are normally very irregular and difficult to control.
Examples: hillside rivulets, brooks, streams, rivers and tidal estuaries.

25. Type of Open Channel
Artificial Channel
Artificial channels are watercourses that are contracted and developed by human.
The properties of artificial channels are based on developers’ requirements and controllable.
Examples: floodways, irrigation canals, drainage ditches and spillways.

26. Artificial Channel
In engineering practice, artificial channels are given different names such as:
canal
flume
chute and drop
sewerage

27. It is a long and mild-sloped channel built on the ground.
Canal
It is a long and mild-sloped channel built on the ground.
Exist in earth surface or coated with concrete, cement, wood or others.

28. It is used in laboratory for research.
Flume
It is a hard channel or passage built from wood, metal or concrete across a depression.
It is used in laboratory for research.

29. Chute is a steep-sloped channel.
Chute and Drop
Chute is a steep-sloped channel.
Drop is similar to a chute, but the change in elevation takes place over a very short distance.

30. It is a closed conduit and built under soil surface.
Sewerage
It is a closed conduit and built under soil surface.
The water is in half-fully flow.

31. TIME’S UP … THANK YOU Addition reading:
Cengel Y. A. And Cimbala J.M. (2010). Fluid mechanics: Fundamentals and applications. McGraw-Hill. UK.
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THANK YOU