CE 7995 Lab Report: Flow and velocity measurements in a river
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Transcript of CE 7995 Lab Report: Flow and velocity measurements in a river
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7/25/2019 CE 7995 Lab Report: Flow and velocity measurements in a river
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CE 799Lab#
Flow and Velocity Measurements
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1.0 INTRODUCTION
%)e &ollowing data was collected on May 1/ $015 in t)e nort) branc) o& t)e Clinton
4ier assessed &rom t)e olcott Mill Metro+ar:Farm in 4ay Mic)igan' %)e
assessment included one cross section at a run ;ust downstream o& a rier crossing'
*mbient air tem+eratures were a++ro
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Figure 2 Hand-Drawn Setch
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2.0 METHODS AND ASSUMPTIONS
%)e data collection site was 101 &t' downstream o& t)e rier crossing' %)is site was
c)osen due to t)e stability o& t)e stream at t)is location since t)is section did not
a++ear to be aAected by t)e crossing nor was it near t)e bend in t)e stream' %)e
Bow a++eared to be steady and t)e water was not turbid at t)is location'
Four diAerent met)ods were utilied to determine t)e Bow at t)is cross8section wit)
elocity o& t)e water at a +articular location widt) and de+t) being t)e data
collected &or eac) Bow calculation' First ocular estimates were made as eac) team
member became acDuainted to t)e stream estimating elocity o& t)e water along
wit) widt) and aerage de+t) o& t)e cross section' 6eeld measurements were
made using leaes and &oam to calculate elocities a&ter measuring t)e widt) o& t)e
cross section and de+t) at t)e re+resentatie +oint along t)e cross section' ot)
measurements allowed &or a better understanding o& t)e stream3s moement on
t)is +articular day )oweer t)ey are not meant to be used &or &uture calculations
and determinations'
%)e t)ird Bow measurement made was done using a mec)anical elocity meter'
%)e mec)anical meter measures elocity ia reolutions o& t)e +ro+eller'
Limitations o& t)is deice include +ossible ariations in elocity measurements due
to disturbances in Bow caused t)e +ro+eller as well as t)e instrument3s ineciency
&or measuring turbulence' %)e >nal Bow measurement was made &rom elocity
determined using an *coustic "o++ler Velocity *"VG meter' "ue to t)e deice3semission o& acoustic signals to measure t)e reBection o& t)e sound waes t)e Bow
o& t)e stream remains undisturbed at t)e +oint o& data collection' %)e stream )ad
sucient turbidity to reBect t)e signal bac: to t)e *"V' For Bow determinations
made using bot) t)e mec)anical Bowmeter and *"V t)e cross section was diided
into two8&oot bins and t)e meter was +laced at t)e center o& eac) bin' (t was
assumed t)at t)e center o& eac) bin +roided t)e re+resentatie de+t) o& t)e entire
bin' %)e >nal bin &or eac) measurement )ad ery low Bow and t)e bin was only 1'5
&t wide rat)er t)an $ &t'
%o ma:e our >nal calculation o& Manning3s roug)ness coecient we also needed to
determine t)e slo+e o& t)e water sur&ace' %o do t)is a stretc) o& rier was used
slig)tly u+stream &rom t)e cross section used to ma:e measurements &or t)e Bow
determination' %)e stretc) used began at a riHe .92 &t' u+stream &rom t)e Bow8
determination cross section and ended at t)e ne
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u+stream &rom t)e Bow8determination cross section' (t was assumed t)at t)e slo+e
o& t)is stretc) o& rier re+resented t)e slo+e at t)e cross section'
3.0 OCULAR ESTIMATES
Eac) team member &or t)e selected cross8section conducted an ocular
estimate o& t)e c)annel Bow' -cular estimates can be a aluable tool &or an
engineerI t)ey +roide an a++ro
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!a"le 2 Field $easurement
Data
$.0 MECHANICAL %ELOCIT&
MEASUREMENT
Velocity measurements were
ta:en across t)e stream using a
mec)anical meter in two8&oot interal
bins' "ue to t)e ariability in stream
Bow elocity measurements were collected once eery >e seconds until
eig)t measurements were collected &or eac) bin' )en ta:ing
measurements &or eac) bin t)e measurement location )eig)t was /0 +ercent
o& t)e de+t) &rom t)e water sur&ace' %)e +articular mec)anical elocity
meter used was a to+ setting wading rod allowing ad;ustment o& t)e
measurement de+t) wit)out getting your )ands wet' %)e elocity
measurements were aeraged &or eac) bin and t)e aerage elocity were
eac) used to calculate t)e Bow rate o& t)e stream' %)e mec)anical elocity
meter data collected is +roided in %able ,'
Stat'o"
ft
De(t)
ft
%elo't* 1
ft/se
%elo't* 2
ft/se
%elo't* 3
ft/se
%elo't* #
ft/se
%elo't* $
ft/se
%elo't* +
ft/se
%elo't* ,
ft/se
%elo't* -
ft/se
Ae!ae
%elo'
t*ft/se
Flft3
$ 0'70 0'5 0'7 0'/ 0'7 0'/ 0'7 0'/ 0'7 0'/ 0
. 1'00 0'9 1'0 1'0 0'2 1'0 0'2 0'9 1'1 0'9 1
/ 1'$5 0'9 0'9 0'2 0'2 0'2 0'9 0'9 0'9 0'9 $
2 1'$0 1'0 1'1 1'0 1'1 1'1 1'0 0'9 1'0 1'0 $
10 1',0 1'$ 1'1 1'0 1'0 1'1 1'1 1'0 1'1 1'1 $
1$ 1'$0 1'. 1'. 1', 1', 1'. 1'1 1'1 1'. 1', ,
1. 1'$0 1'1 1'. 1'5 1'1 1'1 1', 1'. 1'$ 1', ,
1/ 1'10 1'. 1'. 1'. 1'$ 1'1 1', 1'. 1'$ 1', $
12 1'00 1', 1'. 1'. 1'$ 1', 1'5 1', 1'5 1'. $$0 1'10 1', 1'5 1'. 1'$ 1'$ 1'5 1'5 1'. 1'. ,
$$ 1'10 1', 1'$ 1', 1'$ 1'1 1'$ 1'0 1'. 1'$ $
$. 0'90 1'5 1'5 1'. 1'1 1'$ 1'1 1'. 1', 1', $
$/ 1'10 1'. 1', 1'. 1'1 1'. 1'1 1', 1'$ 1', $
$2 1'15 1'. 1'1 1'$ 1'1 1'$ 1'0 1'1 0'9 1'1 $
,0 0'/0 1', 1'. 1'. 1'5 1'5 1'5 1'. 1'. 1'. 1
,$ 0'20 1', 1'1 1'1 1'$ 1'1 1'$ 1'$ 1'1 1'$ 1
Page /
't)ft
De(t)ft
%elo't*
ft/se
Flowft3/se
.,'5 1'02 1'1/ 5.'.7
.,'5 1'02 1'., /7'11
.,'5 1'02 1',1 /1'.1
.,'5 1'02 1'$, 57'2$
.,'5 1'02 1'.$ //'22
.,'5 1'02 1'$9 /0'/$
.,'5 1'02 1'.5 /2',,
*erage 1',, /$',2
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,. 0'20 1'$ 1'1 1'$ 1'1 1'1 1'1 0'9 0'9 1'1 1
,/ 0'25 0'2 0'7 0'2 0'2 0'7 0'9 0'7 0'7 0'2 1
,2 0'90 0'7 0'7 0'7 0'2 0'2 0'2 0'9 0'9 0'2 1
.0 1'00 0'5 0'/ 0'7 0'5 0'7 0'7 0'. 0'/ 0'/ 1
.$ 0'90 0'1 0'0 0'1 0'1 0'1 0'1 0'0 0'1 0'1 0
., 0'75 0'0 0'0 0'0 0'0 0'0 0'0 0'0 0'0 0'0 0
TotalFlow
#
!a"le % $echanical &elocit' $eter Data
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+.0 ACOUSTIC DOPPLER %ELOCIMETER MEASUREMENT
Velocity measurements were also collected across t)e stream using an
acoustic do++ler elocimeter *"VG in t)e same two8&oot interal bins used in
t)e mec)anical elocity meter analysis' %)e ma;or adantages to t)e *"Voer t)e mec)anical unit were being able to measure Bow w)ile not
disturbing t)e region being measured and being able to measure
turbulence' %)e *"V unit used was also to+ setting similar to t)e
mec)anical elocity meter' %)e elocity measurements &or eac) bin were
used to calculate Bow' %)e mec)anical elocity meter data collected is
+roided in %able .'
Stat'o"ft
De(t)ft
%elo't*
ft/se
Flowft3/se
$ 0'75 0'/9 1'55
. 1'10 0'7, 1'/1
/ 1',0 1'00 $'/0
2 1'$0 1'$$ $'9,
10 1',0 1'$5 ,'$5
1$ 1'$5 1'$9 ,'$,
1. 1'$0 1',. ,'$$
1/ 1'$0 1',, ,'19
12 1'10 1',, $'9,$0 1'05 1'.1 $'9/
$$ 1'10 1'$2 $'2$
$. 0'25 1',9 $',/
$/ 1'00 1'19 $',2
$2 1'10 1'12 $'/0
,0 0'70 1',. 1'22
,$ 0'20 1'02 1'7,
,. 0'90 0'92 1'7/
,/ 0'90 0'21 1'./
,2 0'90 0'20 1'...0 1'05 0'50 1'05
.$ 0'90 0',5 0'/,
., 0'.0 0'01 0'01
A!ea#3.+,
$ ft2
Flow #,.$,ft3/se
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!a"le ( AD& $eter Data
,.0 ATER SURFACE SLOPE
%)e water sur&ace slo+e was calculated by sureying t)e eleation at two +ointscorres+onding to an u+stream and downstream riHe' %)e diAerence in )eig)t
between t)e two riHes was 1'$13 and t)e distance between t)e two riHes was ,/73'
%)e resulting water sur&ace slo+e was calculated to be 0'00,, &t&t' %)e surey data
collected to calculate water sur&ace slo+e is +roided in %able 5'
Stat'o"ft
Relat'eate!
S!faeEleat'o"
ft
Slo(eft/ft
Notes
8,97 /',. 888 +stream riHe &or slo+e measurement
8,0 5'1,0'00,$
97urey station ;ust u+stream o& road riercrossing at riHe
0 888 888tart o& surey ta+e ;ust u+stream o& riercrossing
11 888 888 Centerline o& road to cross rier in riHe
101 888 888 Cross8section &or elocity measurements in run
!a"le ) Slo*e Surve' Data
-.0 CALCULATION OF MANNIN4S ROUHNESS COEFFICIENT
%)e measured stream +arameters elocity Bow slo+e etc'G were used to
calculate Manning3s roug)ness coecient &or t)e cross section o& t)e rier
e
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n N 1'.9O4$,O1$G*G
Pa!a6ete! %ale U"'t
-cular EstimateFlow G /0'$0 &t,secField Estimate FlowG /$',2 &t,sec
Mec)anical Flow G ..'/2 &t,sec
*"V Flow G .7'57 &t,sec
idt) .,'5 &t
*erage "e+t) 1'00$, &t
Qydraulic 4adius 4G 0'9521 &t
*rea *G .,'/0 &t$
ater ur&ace lo+eG
0'00,$97 &t&t
Ma""'"7s Ro)"essCoe8'e"t
%ale
-cular Estimate n0'0/0
$
Field Estimate n0'052
1
Mec)anical n0'021
$
*"V n0'07/
$
Ae!ae0.0+-
9
9.0 NARRATI%E
%)e mec)anical Bow measurements and *"V measurement were ery similar
wit)in /R o& eac) ot)er' %)e >eld estimate and ocular estimate were ,1R and $7R
diAerent t)an t)e *"V measurement res+ectiely' Considering t)e general
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