Q f 20 ft 3 s 582 ft 075 ito ls c pv z wa7t 5 pu4

Q
f}
2.0 ft
3
/s
58.2
ft
0.75
Ito
'Ls c
Pv'--'
~
\Z--/wA7""T
_5
(Pu,).,4_?
B'e.J..}l..6'
Pe:>vJc;,
L.)
lJJ
) ::-
bZ.'-(
Ji_,
~.3
t-7 0,..rr
Fo\'2-Ga:-, Tll--e
5
c:... /
,~-;::'l-r~,1.-
"/EiT
u$o
i
77:)
/{:(lb)
r::>
/I.
Downloaded by Mary Joy Lucero ([email protected])
lOMoARcPSD|8236127

FE Review-Fluid Mechanics
38
0
;:
Example: Compute the discharge
rate that
causes the pressure
to drop to vapor pressure.
The pipe between
the reservoir and pump
has a
length of 1,000 ft, diameter
of 3 feet, and friction
factor
(f}
of 0.02.
Neglect minor losses.
For
a
water temperature
of 80°F , the vapor pressure
(Pv)
is 0.51 psia.
atmospheric
pressure
f
10 ft
t
L-==
ll?t..'.)C,
!--
'v-==-
t
J---
J-::
C,,O'L._
;-
::: 3o· p
~ ~
o. ;-, ~(~'~ ) '-
Downloaded by Mary Joy Lucero ([email protected])
lOMoARcPSD|8236127

FE Review-Fluid Mechanics
39
Example: Compute the discharge in each
pipe. Neglect minor losses.
I(
VALV6:
_$
~
I ,._)
f6: ?:tlAP.. J
25
ft
K
1
==
0.359
K-f(L)( 1)
D 2gA2
Pipe L(feet) D(inch) A (ft
2
)
f
K=f(LlD) (ll2gA
2
)
1 3,000 16 1.396 0.020 0.359
2 3,000 12 0.785 0.022
1.
663
3 2,000 8 0.349 0.020 7.649
4
1,000 16 1.396 0.020 0.120
Downloaded by Mary Joy Lucero ([email protected]m)
lOMoARcPSD|8236127

FE Review-Fluid Mechanics
40
The Darcy friction factor for
both of the pipes
&-
shown is 0.024. The total flow rate
is 300 m
3
/h.
What is the flow rate through the
250 mm pipe?
A
rr- (
-)'--
, = -
(:) , I~
'I
::- o.
D \
t(
('AL
\ 6Wb
A-(_::::§ (,
1.
S")"l..
\(
~
-=-
o.
OL\"'
Mz_
...___; ....... ; .... ; .... ;;.,..__., ~ ; ........ , ..... :.-;..__---
{ 6$0 ~ ;
~ ~ o
ffiin
dlameter
3.eio
~
-= (I,
0 q
S-)(
c,,
c,,
~,,?·)
~t..
"'
+-
(o ,
6
L\
4
M._) \} z_
L,
\J'"';
L2- ~\
- = -
P,
Pc..-
"l.
'L
\I
1 :::
LLD,
'1~
=
~
50'1\}:0,
IS°"M)
~ ~
L
l
'DL
(
"32.5"
""')(o.lYM.)
V,
= (,
O'?~JL-
Downloaded by Mary Joy Lucero ([email protected])
lOMoARcPSD|8236127

FE Review-Fluid Mechanics
41
EXAMPLE: Two reservoirs are
connected
850 feet long 6-inch diameter pipe (f
==
0.020).
pump with the
given characteristic curves is used
to lift water from one reservoir
to the
Determine the
discharge rate.
by
a
A
other.
T
100 ft
t
pump
----,0--------:.-----
/80
90
/60
80
140
~0
70
~-
' ~
--
/20
<< ()
00
'cf2-
-
~
+-'
~
(]}
-
(]}
(.) ~
>-
'+-
/00
t::
CJ..~
50
(.)
-·
-~
~
C
-0
.
(.)
(]}
co
80
~
40
·c:;
(]}
"I-..
I Cl)
"+-
"f-
~o
30
w
40
zo
20 /0
0
0
zoo
L/00
soo
800 /000
Discharge Capacity
(gpm)
Downloaded by Mary Joy Lucero ([email protected])
lOMoARcPSD|8236127

FE Review-Fluid Mechanics
42
What is
the hydraulic radius
of the trapezoidal
irrigation
canal shown?
~
,0 b
1 l """
.,,.<--
.. - ••. -•...••
~
.•
~
•.••..
~
...
~
..... ~. ~-~~;___~······
.~· ....... , .,·· .-;-;..,
--"-=-'- ....... =c-.~
.......
,
... ... -- · ..
..
. . . .
.
,
.... -· ..
. .
. . . ...
···· · ···· ... .. .
3
: rm : . .. . . .
.5:
rn
. .
3
m .
· . · . .. ·
1~ .......... ..._ .... ·. ---- ·· · -- · ----
· .. __ •
··· --1 . ... ...... ~·· ·· ......... ..
'"'!"" , ....... --,~,
fl/
p
!?...4-vL
IC--- le.A P
r i./
~
---
----
---
-
-
-
1..1
~
Downloaded by Mary Joy Lucero ([email protected])
lOMoARcPSD|8236127

FE Review-Fluid Mechanics
43
Geometric Elements of Channel Section
example: trapezoidal section
X -
~
;:., - l
top width
T
T
20 ft
~,
6~
-.I
wetted perimeter
:::::
(2-)( /;,.
L)
i)
+
2--oJ+
=
l/ b' CJ~
f'
::-
~
\
1Y-t-
c,,
't..-
~ I ;;, •
l\
¥
hydraulic radius
hydraulic depth
c..
1
w~.J t,...ts,j.. _
w,r.
-
L/ .
I
--1-+--
Downloaded by Mary Joy Lucero ([email protected])
lOMoARcPSD|8236127

FE Review-Fluid Mechanics
44
Example: Compute the discharge
in a
concrete (n
=
0.01 5) channel
with the
previous cross-section and slope of
PJ
lb 7
0.10%.
-
I/\
=
C). C) ( ...'.:::,
f?_e:>ul,J-/
vr=>.S
ce>F~
'.::::>
=-
O . I
o ;( =-
c::> .
00
I
\,L
-=- /.
4 26
0. 015"'
Downloaded by Mary Joy Lucero ([email protected])
lOMoARcPSD|8236127

FE Review-Fluid Mechanics
45
Example:
Compute the normal
depth and
Q
s
n
velocity.
·:. ,·
400
cfs
0.0016
0.025
'/ X
- - - -;,
'f.
=
2..
'I
I - }-
I
-r = )"-J'-
+(ly)'--
,4
=
~z.o
+
(L;
+
(i){2y))
j
(y)
J
'IL
t
(tj/ (
2-} T
Z 0
'--b
~
)
(
zo+(~"'+Y,>')\(y)
/..