
Unit 41: 
Fluid Mechanics 


Unit code:

T/601/1445



QCF level:

4



Credit value:

15






• Aim
The aim of this unit is to extend learners’ knowledge of the principles
of fluid mechanics and the techniques used to predict the behaviour of fluids
in engineering applications.
• Unit abstract
This unit will begin by looking at the forces exerted by a static fluid
on immersed surfaces and the concept of centre of pressure. It also examines a
range of hydraulic devices and systems that incorporate the transmission of
hydraulic pressure. Learners will then examine viscosity in fluids, its
measurement and the characteristics of Newtonian and nonNewtonian fluids.
The unit then examines fluid flow phenomena. These include the
estimation of head loss in pipes, viscous drag around streamlined and bluff
bodies and the concept of Reynolds’ number. It also introduces learners to the
techniques and applications of dimensional analysis. Finally, learners will
examine the operational characteristics of hydraulic machines, in particular
the operating principles of water turbines and pumps.
• Learning outcomes
On successful completion of this unit a
learner will:
1 Be able to determine the behavioural
characteristics and parameters of static fluid systems
2 Understand the effects of viscosity in fluids
3 Be able to determine the behavioural
characteristics and parameters of real fluid flow
4 Understand the operating principles of
hydraulic machines.
Unit content
1 Be able to determine the behavioural
characteristics and parameters of static fluid systems
Immersed
surfaces: rectangular and
circular surfaces eg retaining walls, tank sides, sluice gates,
inspection covers, valve flanges
Centre of pressure: use of parallel axis theorem for immersed rectangular and circular immersed
surfaces
Devices: hydraulic presses; hydraulic jacks; hydraulic accumulators; braking
systems; determine outputs for given inputs
2 Understand the effects of viscosity in fluids
Viscosity: shear stress; shear rate; dynamic
viscosity; kinematic viscosity
Viscosity
measurement: operating
principles and limitations of viscosity measuring devices eg falling
sphere, capillary tube, rotational and orifice viscometers
Real fluids: Newtonian fluids; nonNewtonian fluids
including pseudoplastic, Bingham plastic, Casson plastic and dilatent
fluids
3 Be able to determine the behavioural
characteristics and parameters of real fluid flow
Head losses: head loss in pipes by Darcy’s formula;
Moody diagram; head loss due to sudden enlargement and contraction of
pipe diameter; head loss at entrance to a pipe; head loss in valves; flow
between reservoirs due to gravity; hydraulic gradient; siphons; hammerblow in
pipes
Reynolds’ number: inertia and viscous resistance forces; laminar and turbulent flow;
critical velocities
Viscous drag: dynamic pressure; form drag; skin friction
drag; drag coefficient
Dimensional analysis: checking validity of equations such as those for
pressure at depth; thrust on immersed surfaces and impact of a jet;
forecasting the form of possible equations such as those for Darcy’s formula
and critical velocity in pipes
4 Understand the operating principles of
hydraulic machines
Impact of a jet: power of a jet; normal thrust on a moving flat vane; thrust on a
moving hemispherical cup; velocity diagrams to determine thrust on
moving curved vanes; fluid friction losses; system efficiency
Operating principles of turbines: operating principles, applications and
typical system efficiencies of common turbomachines including the
Pelton wheel, Francis turbine and Kaplan turbine
Operating principles of pumps: operating principles and applications of reciprocating and centrifugal
pumps; head losses; pumping power; power transmitted; system efficiency
Learning outcomes and assessment criteria

Learning outcomes

Assessment criteria for pass




On successful completion of

The learner can:




this unit a learner will:












LO1 Be able to determine the


1.1

determine the hydrostatic pressure and
thrust on



behavioural
characteristics



immersed surfaces



and
parameters of static fluid


1.2

determine the centre of pressure on
immersed



systems







surfaces












1.3

determine the parameters of devices in
which a fluid






is used to transmit force









LO2 Understand the effects of


2.1

explain the characteristics of and
parameters of



viscosity
in fluids



viscosity in fluids





2.2

describe viscosity measurement techniques





2.3

describe the effects of shear force on
Newtonian






and nonNewtonian fluids









LO3 Be able to determine the


3.1

determine head losses in pipeline flow



behavioural
characteristics


3.2

determine Reynolds’ number for a flow
system and



and
parameters of real fluid







assess its significance




flow














3.3

determine viscous drag of bluff and
streamlined






bodies





3.4

apply dimensional analysis to fluid flow









LO4 Understand the operating


4.1

evaluate the impact of a jet of fluid on a
moving vane



principles
of hydraulic


4.2

identify and explain the operating
principles of water



machines







turbines and pumps.















Guidance
Links
This unit has links with Unit 2: Engineering Science and Unit
61: Engineering Thermodynamics.
Essential requirements
Learners will need access to laboratory
facilities suitable for the investigation of viscosity, Reynolds’ number for
pipeline flow and the measurement of drag forces on bluff and streamlined
bodies.
Employer engagement and vocational contexts
Liaison with
industry can help centres provide access to relevant industrial facilities and
related plant. Where possible workbased experience should be used to provide
practical examples of fluid systems.
A visit to a
utilities water treatment plant, pumping station or hydroelectric generating
installation will enhance delivery of the unit.
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