ENGIN1002 Physics: Fluids Practical for Online Students

Running Head: ENGIN1002 PHYSICS: FLUIDS PRACTICAL FOR ONLINE STUDENTS 1
ENGIN1002 Physics: Fluids Practical for Online Students
By(name)
Institutional Affiliation

ENGIN1002 PHYSICS: FLUIDS PRACTICAL FOR ONLINE STUDENTS 2
Table of Contents
1. Objectives....................................................................................................................................1
2. Introduction..................................................................................................................................1
3. Procedure.....................................................................................................................................2
4. Results and Analysis....................................................................................................................3
5. Discussion....................................................................................................................................7
6. Conclusion...................................................................................................................................7
7. Recommendations........................................................................................................................7
8. References....................................................................................................................................7
List of Figures
Figure 1: Relationship between dynamic head and velocity...........................................................4
Figure 2: Relationship between Re and the friction factor, f..........................................................5
Figure 3: Relationship between Re and the loss coefficient, f.........................................................6

ENGIN1002 PHYSICS: FLUIDS PRACTICAL FOR ONLINE STUDENTS 1
Objectives
i) To determine the velocity of a fluid in a pipe using Bernoulli principle.
ii) To determine the friction coefficient f for a straight pipe for different flow rates
iii) To investigate the effect of an abrupt change in the pipe shape to the flow
characteristics of a fluid (water in this case) by determining the loss factor k.
Introduction
Some of the common flow meters used in measuring pipe flow include differential pressures
flowmeters including venture tube, rotameters, and orifice plates electromagnetic flow meter1.
These methods are however not applicable in open channel flows. In most cases flow
measurement in open channel is used in measurement of fluid height as the fluid passes through
an obstruction as a flume or a weir in the channel.
Weirs are of different types. The most common types include broad chested (rectangular) and
sharp-crested (either trapezoidal or triangular) (Mory, 2013). Sharp-crested weirs are used in the
measurement of discharge of smaller channels while broad-crested weirs are used in the
measurement of large canals and river’s channels (Monin & Yaglom, 2013).
In this case the flow rate is computed using the formula
Q=Cd 2
3 B √ ( 2 g ) h
3
2
Where;
Cd is the coefficient of discharge.
h is the height measured from the top of the weir to the water surface.
B is the width of the water channel.
g is the acceleration due to gravity = 9.81 m/s2
Therefore, it is easy to calculate the flow rate Q by measuring h.
1

ENGIN1002 PHYSICS: FLUIDS PRACTICAL FOR ONLINE STUDENTS 2
Friction loss in pipes
In pipes, friction loss is concerned with the loss in head in a pipe as the fluid flow changes from
laminar to turbulent, for example by the introduction of a bent in a straight pipe. Pipe flow
studies are useful in determining the Reynolds number. To determine head loss, two manometers
are connected at different places along the length of the pipe. In the region with less turbulent
flow which can be considered laminar, the reading indicated by the manometer is lower than the
reading indicated by a manometer in a turbulent region which records high pressures (Institute et
al., 2012). The loss in head is due to effects of resistance to the motion of the fluid and is
expressed as a function of the loss factor f which is in turn related to the Reynolds number.
Head loss is given by the following equation:hL=f u2
2 g
L
D ,
Where,
hL is the head loss due to friction
u is the fluid velocity
L is the length of the pipe between the two manometers
D is the internal diameter of the pipe
In addition to the loss of head due to friction which is regarded as the major cause of head loss,
there are also other causes of head loss considered to be minor (Granger, 2012). These include
bends, open or partially closed valves, abrupt changes in contraction and expansion (Pletcher,
Tannehill, & Anderson, 2016). Head loss can also be expressed as a function of the loss factor k
as the equation below shows.
hL=k u2
2 g
Where,
k is the loss factor and u is the velocity.
2