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UNIT IV
PART A
1. What is meant by energy loss in a pipe?
When the fluid flows through a pipe, it loses some energy or head due to
frictional resistance and other reasons. It is called energy loss. The losses are
classified as; Major losses and Minor losses
2. Explain the major losses in a pipe.
The major energy losses in a pipe is mainly due to the frictional
resistance caused by the shear force between the fluid particles and boundary
walls of the pipe and also due to viscosity of the fluid.
3. Explain minor losses in a pipe.
The loss of energy or head due to change of velocity of the flowing
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fluid in magnitude or direction is called minor losses. It includes: sudden
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expansion of the pipe, sudden contraction of the pipe, bend in a pipe, pipe
fittings and obstruction in the pipe, etc.
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4. State Darcy-Weisbach equation OR What is the expression for head loss due to
friction?
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hf = 4flv2 / 2gd
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where, h f = Head loss due to friction (m), L = Length
of the pipe (m),d = Diameter of the pipe (m),
where V varies from 1.5 to 2.0.
5. What is compound pipe or pipes in series?
When the pipes of different length and different diameters are
connected end to end,then the pipes are called as compound pipes or pipes
in series.
6. What is mean by parallel pipe and write the governing equations?
When the pipe divides into two or more branches and again join
together downstreamto form a single pipe then it is called as pipes in
parallel. The governing equations are:
Q1 = Q2 + Q3 hf1 = hf2
7. Define equivalent pipe and write the equation to obtain equivalent pipe diameter.
The single pipe replacing the compound pipe with same diameter
without change indischarge and head loss is known as equivalent pipe.\
8. Define the terms a) Hydraulic gradient line [HGL] b) Total Energy line [TEL]
Hydraulic gradient line: It is defined as the line which gives the sum of
pressure headand datum head of a flowing fluid in a pipe with respect the
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4931_Grace College of Engineering
www.Poriyaan.in
` UNIT 5 (PART A)
1. Mention the range of Reynold’s number for laminar and turbulent flow in a pipe.
If the Reynolds number is less than 2000, the flow is laminar. But if the
Reynold’s number is greater than 4000, the flow is turbulent flow.
2. What does Hagen-Poiseulle’s equation refer to?
The equation refers to the value of loss of head in a pipe of length ‘L’ due to
viscosityin a laminar flow.
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3. What are the factors to be determined when viscous fluid flows through the
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circular pipe?
The factors to be determined are:
i. Velocity distribution across the section.
ii. Ratio of maximum velocity to the average velocity.
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iii. Shear stress distribution.
iv. Drop of pressure for a given length
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4. Define kinetic energy correction factor?
Kinetic energy factor is defined as the ratio of the kinetic energy of the flow per sec based
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on actual velocity across a section to the kinetic energy of the flow per sec based on average
velocity across the same section. It is denoted by (α).
5. Define Boundary layer.
When a real fluid flow passed a solid boundary, fluid layer is adhered to the solid
boundary. Due to adhesion fluid undergoes retardation thereby developing a small region
in the immediate vicinity of the boundary. This region is known as boundary layer.
6. What is mean by boundary layer growth?
At subsequent points downstream of the leading edge, the boundary layer region
increases because the retarded fluid is further retarded. This is referred as growth of
boundary layer.
7. Classification of boundary layer?
(i) Laminar boundary layer
(ii) Transition
(iii)Turbulent
8. Define Laminar boundary layer?
Near the leading edge of the surface of the plate the thickness of boundary layer
is small and flow is laminar. This layer of fluid is said to be laminar boundary layer.
The length of the plate from the leading edge, upto which laminar boundary
layer exists is called as laminar zone. In this zone the velocity profile is parabolic.
9. Define transition zone?
After laminar zone, the laminar boundary layer becomes unstable and the fluid motion
transformed to turbulent boundary layer. This short length over which the changes taking place
is called as transition zone.
10. Define Turbulent boundary?
Further downstream of transition zone, the boundary layer is turbulent and
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