College of EngineeringFLUIDS LABORATORY
Measurement of Velocity Profile andHead Loss/Friction Factor in Pipe Flow
Purpose
Re
To measure flow rate, friction factor, and velocity profile in pipe flows with smooth and rough walls and specified turbulent-
flow Reynolds number ( ) and compare the results with benchmark data , including uncertainty analysis for the friction
factor and velocity profile.
Test Design
Air is blown into a large reservoir located at the upstream end of the pipe system. Pressure built up in the reservoir forces air to
flow downstream through any of the three straight experimental pipes. At the downstream end of the system, the air is
directed downward and back through any of the three other pipes fitted with venturi meters.
Measurement Systems
Results
Block diagram of the experimental determination of the friction factor
Data Analysis
�
�
�
Obtain and plot the velocity profile and
compare with benchmark data
Determine the friction factor using the
pressure measurements and the Darcy-
Weisbach equation and compare with
benchmark data
Estimate experimental uncertainties
Comparison between reference data for the velocity profile and friction
factor and the experimental resultsBlock diagram of the velocity measurement
Measurement of Velocity Profile andHead Loss/Friction Factor in Pipe FlowMeasurement of Velocity Profile and
Head Loss/Friction Factor in Pipe Flow
Air-flow pipe system
Pressuretaps
Motorcontroller
Floor
6’-6
”
Re
se
rvo
ir
2.0” smooth
0.5” smooth
2.0” rough
Reliefvalves
Blower
D = 2.0”D = 1.0”
D = 0.5”
tt
t
36’
Venturi meter gate valvesThermometer
1 2 3 4
Valve manifold
Simplemanometer
Pitot tubehousings
Valves
Differentialmanometer
Venturi meters
r/R
-1.00 -0.75 -0.50 -0.25 0.00 0.25 0.50 0.75 1.00
u/U
max
0.0
0.2
0.4
0.6
0.8
1.0
Reference data (Schlichting, 1968) - Re = 1.1e5
Smooth Pipe (Re=1.56e5)
Rough Pipe (Re=1.49e5)
EXPERIMENTALRESULT
w
w
T
TB T, P
STAGNATIONPRESSURE
STATICPRESSURE
EXPERIMENTAL ERROR SOURCES
INDIVIDUALMEASUREMENT
SYSTEMS
MEASUREMENTOF INDIVIDUAL
VARIABLES
DATA REDUCTIONEQUATIONS
z
B , P
SM
B , Pu u
u
= F(T )�
�
u = F( , , z , z )� �
2( ) g�
�
½
=
TEMPERATUREWATER
TEMPERATUREAIR
w
a stag
a
T
TB T, Pa
z
w
w
w
SMstag
zSM
stag
z
B , P
SMstat
zSM
stat
zSM
stat
= F(T )a
aa SM
stagSM
stat
zSM
stag
- zSM
stat
w
a
EXPERIMENTALRESULTS
EXPERIMENTAL ERROR SOURCES
INDIVIDUALMEASUREMENT
SYSTEMS
MEASUREMENTOF INDIVIDUAL
VARIABLES
DATA REDUCTIONEQUATIONS
TEMPERATUREWATER
TEMPERATUREAIR
fB , P
VENTURIPRESSURE
PIPEPRESSURE
f = F( , , z , Q =� � )a
a
wg D�
8LQ
�
�
Q = F( z )�
w
w
T
TBT
, P
z
zB , P
f f
SM
SMww
DM
SM
2
2
5
aT
TBT
, Paa
zSM
z
zB , P
DM
DMz
DM
= F(T )�
�
( )
w
= F(T )a
zSM
i
- zSM
j
w
a
0.002
0.001
0.0008
0.0006
0.0004
Smooth Pipe
Rough Pipe
104
105
106
Reynolds Number Re =VD
�
0.015
0.016
0.017
0.018
0.019
0.020
0.021
0.022
0.023
0.024
0.025
Frictio
nF
acto
rf
=h
f
(L/D
)V2 /(
2g
)
Re
lative
Ro
ug
hn
ess,
/D�
Uncertainty band for
+5% in �Smooth Pipe
Rough Pipe
Re 1.5 x 105
Reference Data(Moody Diagram)
