Hydraulic for Civil Engineering | Report

Hydraulic for civil engineering
Introduction
Distribution system of fresh water would have various infrastructures that include collections,
treatment, transmission, storage and distribution to various sectors. The system of water would
always be required to meet commercial, public and industrial activities. The supplied water
would fulfilled both quantity and quality requirements.
Human life is dependent on water as is the case with all animal and plant life on the planet. We
need water for growing food, generation of power, running of factories and generally we require
water as a vital part of our daily lives. About 70 liters of basic needs per person per day would
require water. This requires the need for water to ensure a basic personal standards and
household hygiene sufficient for health maintenance. The consequences of insufficient water
supply would cause disease, energy and time expected on routine collection. .
The process of distributing water in each and every section of a given region would attract
various factors that always would be considered. To prevent obstacles that might be encountered
by the water being transported, measurements of the water rate, the size of the pipes and the open
channel, the slope of the floor, the pressure exerted and the factors that could cause water flow
resistance would be determined and their effectiveness ensured.
The system of fluid flow head loss components would include friction loss conduit loss through
their fittings like tee, elbows valves and reducers. These types of losses normally would be
classified as minor loss while major loss incorporates significant multiplicity of fittings.
Objectives
The main goals which would be reached at the end of the study would include
1. To assess problems with hydrostatics and hydrodynamics
2. To determining the forces exerted on resting fluids and in motion
3. To determining appropriate water distribution pipe sizes
4. To assess the hydrostatic pressure on substructures that would be exerted.
5.

Calculations
Task 1
ai) Pressure in the pipe
Given:
Height = 100 m
Pressure = ρ * g * h
Where,
Density of water = 1000 kg/m3
g = 9.81 N/kg
Pressure = 9.81 * 1000 * 100
= 981,000 N/m2
1 bar = 100000 N/m2
Representing the vaklues in bar
= 981,000/100000
= 9.81 bar
ii) Pressure in the open channel
Given:
Height = 100 m
Pressure = ρ * g * h
Where,
Density of water = 1000 kg/m3
g = 9.81 N/kg
Pressure = 9.81 * 1000 * 100
= 981,000 N/m2
1 bar = 100000 N/m2

Representing the vaklues in bar
= 981,000/100000
= 9.81 b
Pressure is equivalent to force per unit area and in liquid it be would be presented as, P = ρ * g *
h, pressure in this case from the calculation would be equivalent the reason being all the variable
amounts are maintained.
b) Types of forces that resists water flow in pipes
i) Viscosity
Viscosity refers to the measure of resistance of the fluid that flows. The resisistance of the fluid
flow in pipes would be as a result of the existence of internal friction. Large internal friction
would be produced when the fluid that flows would have large viscosity. Furthermore, less
internal friction would be produced when the fluid that flows through the pipe would have low
visicosity (Jha, Cueto-Felgueroso and Juanes, 2011).
ii) Boundaries
Thick boundary layers would increase the shear stress that would resist the flow of the liquid in
the pipes, similarly the thin boundary would decrease the shear stress that would partially resist
the flow of the liquid in the pipes. .
c) Effects of water temperatures on forces that resists water flow in pipes
High temperatures of water impact the structure of water molecules and in the process it enable
the molecules to move fast and overcome the binding forces of the water molecules, therefore
reducing both viscosity and boundary layers (Aladag et al., 2012).
d) Difference between laminar and turbulent flow
The following are differences between laminar and turbulent (Massey, Bernards and Ward-
Smith, 2012)
Laminar flow Turbulent flow
The fluid layers do not cross each other
because they move parallel
The fluid layers cross each other since they do
not move parallel
It would occur in small size pipes and when
velocity of flow would be low
It would occur in large size pipes and when
velocity of flow would be high
The Reynold’s number ≤ 2000 The Reynold’s number ≥ 4000

e) Reynolds number and its relation to turbulent flow
Reynolds number is defined as the product of length times velocity times density divided by the
coefficient of viscosity (Qian et al., 2012).
This would be represented as;
Re = V avg D
v = ρV avg D
μ
Where,
Vavg = average velocity
D = diameter
v = μ
ρ = kinematic velocity
 The flow in pipes would be turbulent for Re ≥ 4000
f) Boundary layer and how it is affected by water flow surface roughness
Boundary layer is defined as a comparatively thin fluid layer near a body’s surface submerged in
a fluid flow.
 As the laminar layer of roughness grows in thickness, it becomes unstable and can then
be converted into a turbulent boundary layer where the fluid particles begin to move
haphazardly.
g) Reduction of water flow resistance in pipes and open channel
Reducing viscosity would reduce water flow resistance both in open channel and pipes through
reducing the friction between water and surface. This would also result in low shear stress to a
body as the water flows through it.
h) Methods involved in supply addition water in town without disrupting the current
water supply
Increase in water supply would be piped in the city if more and larger water reservoirs were
installed and the water they supply directed towards the initial distribution of pipes. Increased
number of reservoirs would mean that more water would be supplied while maintaining the
initial distribution pipes would means that there would be no water supply disruptions.
Task 2
a) Calculation of maximum depth of flow using Manning formula
Open channel