Report 3 flow channel

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1.0 SUMMARY

This experiment was conducted by allowing the water pump to fill the flow channel first until the

water is not flowing out. From that, the zero base H was determined by using the vernier hook.

The H of the flow water is taken as the pointer attached to the vernier hook touch the surface of

the water. The H of the flowing water is varied in this experiment for each weir used. For

Rectangular notch, there are four different H used, while the !notch only three H is plausible for

the weir that has been supplied to us. "fter a stable flow was achieved for every H, the time

taken for the flow of #$ water was taken and the flow rate of the weir was determined. %y that,

the coefficient of discharge for every weir can be determined by using the weir e&uation.

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2.0 INTRODUCTION

The Flow over 'eir apparatus is an experiment conducted to study the effect of different weirs to

the flow of water in a channel. The experiment was conducted by altering the type of weirs plates

at the end of the flow channel on the Hydraulic %ench ! Rectangular notch, !notch. The

apparatus consists of(

)* 'ater inlet that comes from a water pump.

+* Flow channel.

#* tifling %affle that is located in the flow channel to ensure smooth flow condition in

the channel.

-* " vernier hook with a pointer needle mounted on top of the flow channel.

* 'eirs plates ! Rectangular notch, !notch that is mounted at the end of the channel

flow of the Hydraulic %ench.

The flow rate of the channel will be recorded and by using the weir e&uation, the coefficient of

discharge for each weir will be determined at the end of the experiment.

3.0 AIM

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The ob/ectives of doing this experiment are(

)* To determine the characteristics of open!channel flow over a rectangular notch and !

notch.

+* To determine the discharge coefficients for both notch.

4.0 THEORY

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The experiment conducted for the flow over weirs is aimed to study the relationship between the

discharge coefficient and the factors that may affect the flow of the water. 'eirs are obstacles or

barriers that are placed at a flow channel to alter its flow characteristics. The uses of weirs are

mostly to calculate the discharge of the flowing water. The structure of weirs when placed at a

flow channel, will increase the water level, H, which is significant for the flow rate of the water.

There are many types of weirs that are different in shapes. The shapes of the weir will determine

their discharge coefficient for the channel flow. The types of weirs used in this experiment are

the rectangular notch and the !notch. The rectangular notch is commonly used in calculating

discharge of water. The width of the weirs and the width of the channel flow will are significant

for the water flowing. The !notch is a triangular shaped weir which is usually used to measure

small discharge value. The upper section of the !notch is usually above the water level, making

the flow of water is always in triangular shape, thus easier for the cross sectional area

calculation. 0n many cases, the !notch weir is preferred more in low discharge condition as the

head above the weir crest is more sensitive to changes in the flow compared to rectangular weir1

giving more accurate data.

5.0 APPARATUS

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5.1 Part A: Viscsit! " #i$%i& %si'( )*as%ri'( c!#i'&*r

The apparatus used in this experiment are(

Hydraulic %ench

tilling %affle ernier Hook 'eir 2lates( Rectangular 3otch and !notch 'ater 4hannel ump Tank topwatch 2ump witch 2ump

+.0 PROCEDURES

)* The weir apparatus on the hydraulic bench is leveled and the rectangular notch weir is

installed.

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+* The hydraulic bench flow control valve was opened slowly to admit water to the

channel until the water discharges over the weir plate. The water level is ensured even

with the crest of the weir.

#* The flow control valve was closed and the water level was stabilized.

-* The ernier 5auge was set up to a datum reading using the top of the hook. Thegauge was positioned about half away between the notch plate and stilling baffle.

* 'ater was admitted to the channel. The water was ad/usted by using the hydraulic

bench flow control to obtain heads 6H*.

7* The head readings in every increasing of about ) cm were taken by waiting for water

flow condition to stabilize.8* tep - and step was repeated for different flow rate.

9* The readings of volume and time were taken by using the volumetric tank to

determine flow rate.

:* The notch with !notch was replaced after finished with rectangular notch.);* The result was recorded in the tables.

,.0 RESU-T

,.1 R*cta'(%#ar Ntc

V#%)*

/-

H*i(t H

/)

Ti)* /s A*ra(*

Ti)* /s # Rat* /)3

6sT1 T2 T3

# ;.;) 9.8- 8.9+ 8.89 9.)) ;.;;;;

# ;.;+ ).-+ )9.# )8.## )8.;# ;.;;;)9

# ;.;# 9.9# 9.): 9.) 9.) ;.;;;#

# ;.;- .8; .-+ 7.7 .7 ;.;;;-

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30 mm

# ;.; #.8: #.79 #.7# #.8; ;.;;;9)

-( H -( 263 C& H67

!+.;; !-.+: ;.;;)#: ;.9+9 ;.##

!).8; !#.8; ;.;;#)- ;.8;#; ;.78

!).+ !#.-; ;.;;-:: ;.879 ).;;

!).-; !#.+79 ;.;;77# ;.87)# ).##

!).#; !#.;:+ ;.;;98; ;.9)97 ).78

,.2 V8Ntc

V#%)*

/-

H*i(t H

/)

Ti)* /sA*ra(*

Ti)* /s

# Rat*

/)96s265 C&

T1 T2 T3

# ;.;) 7-.#9 7+.#9 78.+9 7-.79 ;.;;;; ;.;)9 ).:7#;

# ;.;+ ):.++ )9.7# )9.8+ )9.97 ;.;;;)7 ;.;#;+ ).):;;

# ;.;# 9.)# 9.79 9.9) 9.- ;.;;;# ;.;-) ;.:#:# ;.;- #.:; #.:7 #.97 #.:) ;.;;;88 ;.;78 ).;)-:

.0 CA-CU-ATIONS

.1 R*cta'(%#ar Ntc

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Flowrate ,Q=volume

time

) $ < ;.;;;# m=

Q=Cd2

3B2 gH

3

2

'here, 4d < 4oefficient of discharge

% < 'idth of notch

H < Head above bottom of notch

> < Flow rate

.1.1 1str*a&i'(

Height, H < ;.;) m

"verage time < 9.)) s

olume < ;.;;# m=

% < ;.;# m

> s

). Eunus ". 4engel, ohn G. 4imbala. 6+;)-*. Fluid Mechanics Fundamental and

Applications. ingapore. Gc 5raw Hill ducation

+. I ubramanya. 6+;;:*.Flow in Open Channel. 3ew Delhi. Tata Gc5raw!Hill

12.2 I't*r'*t

). The ngineering Toolbox. 6+;)+*. 'eirs!Flow Rate Geasure. Retrieved on +8 eptember

+;)-. http://www.engineeringtoolbox.com/weirs-flow-rate-d_!".html". 'ikipedia. 6+;)-*. 'eir. Retrieved on +8 eptember +;)-.

http://en.wi#ipedia.org/wi#i/$eir

%. EouTube. 6+;)#*. Flow Cver 'eirs. Retrieved on +9 eptember +;)-.

http://www.&outube.com/watch'()o*+,e-&0

1. 4ussons Technology. 6+;);*. Flow Cver 'eirs. Retrieved on +8 eptember +;)-.

http://www.cussons.m&2en.co.u#/3OF4$A50/6art/6A54.,4M

13. APPENDICES

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PUMP SWITCH VERNIER

ECTANGULAR NOTCH WITH STILLING BAFFLE

ome of apparatus and materials used for this experiment(

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RECTANGULAR NOTCH

PUMPVOLUMETRIC TANK

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STILLING BAFFLECONTROL VALVE

SUMP TANK

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Report 3 flow channel

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