Unit-43-Hydraulics Tasks 2022

Unit 43 Hydraulics 1
UNIT 43 HYDRAULICS
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Unit 43 Hydraulics 2
TASK 1
From the parameters provided:
Height of pipe, H = 100m
Density of water, ρ = 1000kg/m3
Earth’s Gravitational Force, g = 10 N/kg
From the Formula of Pressure in Fluids, Pressure = Height of pipe x Density of water x Earth’s
Gravity
T heefore , Pressure∈ Pipe=10 m x 1000 kg/m3 x 10 N/kg
Pressure ∈Pipe , P=1,000,000 N /m2
Since 100,000 N/m2 = 1 Bar
Then Pressure ∈Pipe , P=10 ̄¿
(Ghosh et al., 2014)
In open channel, the flow of water takes place because of atmospheric pressure, therefore, the
pressure in the open channel will be:
Pressure in Open Channel, P = Atmospheric Pressure
= 100,000 N/m2
From the determination of pressure developed in open channel and pressure developed in pipe, it
is clear that the two pressures are clear and also the open channel pressure depend on
atmospheric pressure while in pipe flow pressure depend on hydraulic pressure.
(Ercan et al., 2013)

Unit 43 Hydraulics 3
Viscosity: This resistive force is defined as the internal friction within a fluids that makes it resist
to flow. This resistive viscosity force occur between the fluid itself and between the surrounding
and the fluid (Jamshidnia et al., 2010).
Boundary layer effects: This effect is caused by the tendency of the fluid to stick on the solid
boundary near it. Therefore, no matter how easily or fast the fluid far from the boundary may be
flowing, the fluid close to the boundary has to gradually slow down and come to ultimate stop at
the boundary.
Effects of Temperature on Viscosity
In a liquid, the viscosity increases with an increase in temperature since increasing the
temperature decrease the cohesive forces which increasing the molecular interchange rate
simultaneously. The temperature increase causes the kinetic and thermal energies to increase
hence the molecules increase their mobility. The attractive binding energy is lowered and hence
the reduction in viscosity. The result show that the viscosity is minimized with the temperature
increase (Xenos, 2013).
Effects of Temperature on Boundary Layer
An increase in temperature of a liquid flowing decreases the wall of thermal boundary layer until
the flow temperature under the thermal boundary layer becomes 99% of the incoming fluid
temperature. Therefore, an increase in temperature decreases the effects boundary layer (Garai et
al., 2013).
Laminar flow is an orderly and smooth fluid flow while turbulent flow is a chaotic and rough
flow of fluids. A significant factor that determines if the flow if laminar or turbulent is Reynolds
number. A turbulent flow takes place at high Reynolds number greater than 3000 while a
laminar flow takes place at Reynolds number≤ 2300.

Unit 43 Hydraulics 4
The Reynolds number is a quantity that is dimensionless and significant in fluid mechanism used
to assist in the prediction of flow patterns in different situations of fluid flow. It is the ratio of
viscous forces to inertia forces and is a suitable perimeter for determining the conditions of flow
which may be turbulent or laminar. At high Reynolds number, turbulence results from the
difference in the direction and speed of fluid, while at low Reynolds number, the flow tends to be
dominated by smooth or laminar flow.
Therefore, the Reynolds number is related to the turbulent flow when the ratio of inertia forces to
viscous forces is high resulting into high Reynolds number hence the flow will be turbulent
caused by irregular movement of fluid particles.
Boundary layer is defined as the fluid layer of the flowing liquid of gas in immediately vicinity
with the bounding surface especially where the impacts of viscosity are substantial. The
roughness of the surface over which water is flowing affects the type of flow of fluid
The smooth surface result in laminar flow of the fluid hence the particles of fluid move in a
straight line. A rough surface result in turbulent flow due to irregular movement of the fluid
particles on top of a rough surface (Manneville, 2017).
Increasing the water temperature: The resistance of water flow can be reduced by increasing the
temperature of water flowing which reduces the viscosity of water hence reducing the resistance
of water flowing in open channel or in a pipe.
Using smoother pipe or vessel without any disorders: By using smoother pipe of vessel, the flow
of water will be laminar creating very little friction or distance hence reducing the resistance of
water flow in pipe system or open channel.