Description
I have a lab report for water resources Haydraulic lab engineering and I did the excel calculations I just need help writing the report
Introduction (10 points)
The introduction should be a paragraph that contains the goals of the lab and an overview of
what the reader can expect to find within the report.
ï‚·
State the objective of the lab exercise. Though this is provided in the lab documents, the
purpose should be restated in your own words.
ï‚·
Provide a brief overview or “roadmap†of the report contents
.
Results:
This is the only section in which results should be introduced, present your final results from the
analysis(tables). Start this section with a brief description of what your data shows. Give your
reader a context in which to view the data. Present only your information (raw data, tables from
excel sheet, graphs…etc.)
Discussion:
You should explain your results and their ramifications by answering the questions
provided in the procedures (usually it is 3 to 5 questions). You can include details of the
principles, relationships, generalizations, and consequences of your experiment. You must
demonstrate that you understand your investigation and corresponding results. Be sure to relate
your interpretation and discussion back to your objectives. Do your data answer your original
question? You should also include a discussion of possible errors and exceptions. If relevant or
available, discuss how your results compare pertinent standards.
A good conclusion is usually quite short. A
few sentences should be sufficient. Restate your numerical results, but do not editorialize about
your results.
Conclusion:
Summarize the major points of your memo. A good conclusion is usually quite short. A
few sentences should be sufficient. Restate your numerical results, but do not editorialize about
your results.
.
References (2.5 points)
List all your reference writing
Hints
A lab report is considered a technical report. As such, it must be professional and neat. The
report must be written with a word processor of your choice. All drawings must be made with a
straight-edge and clearly labeled or drawn on the computer. Plots are an integral part of
technical reports and must be professional:
•
Plots must be computer generated;
•
Scales must be readable to the same accuracy as the data obtained during
the test;
•
Axes must be labelled;
•
Units of variables must be shown;
•
Various run results must be distinguished by different symbols and/or
colors and each curve must be identified by a legend or a title;
•
Curves derived from data must show experimental data points;
•
Graphs must be drawn as smooth curves that represent an average of the
experimentally determined data.
•
Curves derived from an equation should contain no symbols, but show the
equation of the curve;
•
Graphs must be labeled/legend
A portion of the grade for each lab memo will be based on the writing itself.
•
Be as clear, direct and concise as you can. Grammar, spelling, clarity, and
style will all be considered.
•
Pay attention to tense. When describing established, factual material, the
present tense can be used. A discussion section is generally written in the
present tense. Even though you are discussing past results, you are
interpreting them now. Completed procedures are usually referred to in the
past tense.
I’m working on a engineering writing question and need support to help me understand better.
I’m working on an engineering report and need support to help me study.
I have a lab report for water resources engineering and I did the excel calculations I just need help writing the report
Introduction (10 points)
The introduction should be a paragraph that contains the goals of the lab and an overview of
what the reader can expect to find within the report.
ï‚·
State the objective of the lab exercise. Though this is provided in the lab documents, the
purpose should be restated in your own words.
ï‚·
Provide a brief overview or “roadmap†of the report contents
.
Results:
This is the only section in which results should be introduced, present your final results from the
analysis(tables). Start this section with a brief description of what your data shows. Give your
reader a context in which to view the data. Present only your information (raw data, tables from
excel sheet, graphs…etc.)
Discussion:
You should explain your results and their ramifications by answering the questions
provided in the procedures (usually it is 3 to 5 questions). You can include details of the
principles, relationships, generalizations, and consequences of your experiment. You must
demonstrate that you understand your investigation and corresponding results. Be sure to relate
your interpretation and discussion back to your objectives. Do your data answer your original
question? You should also include a discussion of possible errors and exceptions. If relevant or
available, discuss how your results compare pertinent standards.
A good conclusion is usually quite short. A
few sentences should be sufficient. Restate your numerical results, but do not editorialize about
your results.
Conclusion:
Summarize the major points of your memo. A good conclusion is usually quite short. A
few sentences should be sufficient. Restate your numerical results, but do not editorialize about
your results.
.
References (2.5 points)
List all your reference writing
Hints
A lab report is considered a technical report. As such, it must be professional and neat. The
report must be written with a word processor of your choice. All drawings must be made with a
straight-edge and clearly labeled or drawn on the computer. Plots are an integral part of
technical reports and must be professional:
•
Plots must be computer generated;
•
Scales must be readable to the same accuracy as the data obtained during
the test;
•
Axes must be labelled;
•
Units of variables must be shown;
•
Various run results must be distinguished by different symbols and/or
colors and each curve must be identified by a legend or a title;
•
Curves derived from data must show experimental data points;
•
Graphs must be drawn as smooth curves that represent an average of the
experimentally determined data.
•
Curves derived from an equation should contain no symbols, but show the
equation of the curve;
•
Graphs must be labeled/legend
A portion of the grade for each lab memo will be based on the writing itself.
•
Be as clear, direct and concise as you can. Grammar, spelling, clarity, and
style will all be considered.
•
Pay attention to tense. When describing established, factual material, the
present tense can be used. A discussion section is generally written in the
present tense. Even though you are discussing past results, you are
interpreting them now. Completed procedures are usually referred to in the
past tense.
Hydraulics Laboratory
Flow Over a Sharp-Crested Weir — PROCEDURES
Recommended Reading:
Crowe, C.T., D.F. Elger and J.A. Roberson Engineering Fluid Mechanics, 8th ed., John Wiley
and Sons, 2005, pp. 555-559
References:
1.
Brater, E.F. and H.W. King, Handbook of Hydraulics, 6th ed., McGraw-Hill, Inc.,
1976
2.
Daugherty, R., J. Franzini, and E. J. Finnemore, Fluid Mechanics with
Engineering Applications, 8th ed., McGraw-Hill, Inc., 1985.
Objectives:
1.
To examine the fundamental characteristics of flow over two types of sharp-crested weirs
2.
To measure the coefficient discharge values of a rectangular and triangular weir
Apparatus:
1. Half meter flume equipped with a sharp-crested weir and manometer board
2. Triangular weir in return-flow channel
3. Water surface gages
Experimental Procedure:
1. Experiment Set-up
a.
Open the surge tank valve and turn on the large pump. Close the drain valve on the flume
head tank and open the gate on the downstream end of the flume.
b.
Open the feed valve and fill the head tank until it overflows the weir. Operate the system
in this mode until you see overflow from the triangular weir in the sump.
c.
Close the downstream gate on the flume. Continue inflow until the flume is about
one-third full. Then close the feed valve. (The water level should be below the weir crest. If it
is not, drain some water out through the downstream gate.) Check that all the water levels in the
piezometers are at the same elevations as in the flume, both upstream and downstream of the
weir. If not, bleed air from the flexible tubing by detaching the tubing from the piezometer,
letting water run out until no bubbles are seen, and then re-attach.
When you are satisfied that the air is out, and the piezometers are reading correctly,
completely drain the flume by opening the downstream gate. Leave this gate open for the rest of
the lab. When the flume is empty, read the water levels in the piezometers they should be at the
same level, record this value as your “zero†value for manometers.
d.
e.
Use the downstream point gage to measure the bottom elevation of the flume at the
various tap locations, record this as your “zero†value for the point gage. Use the upstream point
gage to measure the static water elevation (i.e. no flow) at the weir crest height and the bottom of
the flume. (This is the height of the weir.) Make sure the water height is right at the weir crest
elevation. The weir leaks a little, so you may have to introduce a little additional water to bring
the static water level to the height of the weir.
f.
With no flow, use the point gage in the return channel to measure the elevations of water
surface at the vertex of the Triangular and the bottom of the channel. Record this as the weir height
in the concrete channel
2. Calibrate the rectangular and Triangular weirs.
a. Vent the nappe. Establish a steady flow and record the flowrate from the in-line flowmeter.
b.
Using the upstream point gage, measure and record the water levels (head) at the
rectangular weir and at the Triangular weir. Note: Because of the large storage volume in the
return channel, the flow over the Triangular weir may lag the flow over the rectangular weir by a
number of minutes. Don’t record the triangular elevations prematurely. Wait until the level is
steady.
c.
Repeat steps (a) and (b) for at least five more flows.
3. Shut-down
a. Close the flume feed valve. Open the drain valve on the head tank.
b. Turn off the pump and close the surge tank valve.
Unvented nappe
Vented nappe
Calculations:
1. Plot the flow Qmeassured in cfs (y-axis) against H3/2 (both point gage and manometer) for the
rectangular weir and H5/2 for the triangular weir (x-axis). Pass a trend line through zero. Use
the slope of the trend line to calculate the discharge coefficients (Cw) for each weir.
2. Plot Qtheory (x-axis) vs. Qmeasured (y-axis). Compare the plot with equation in your class
notes. Show equation of the trendline on graph.
3.
For each trial, calculate Cd for the rectangular weir using the following equation:
[1]
This equation is based on measurements at the Karlsruhe Hydraulic Laboratory in Germany.
H is the height of water over the weir (ft) and P is the height of the weir itself
(ft). Also for each trial, read the value of C d for the triangular weir from the following
[2]
figure.
Document these calculations in your spreadsheet and calculate the mean value of Cd for each
weir.
4. Provide the following hand calculations: (1) Duplicate the spreadsheet calculations (both
weirs) for one flowrate. (2) Calculation of Cd using the Karlsruhe equation. (3) Calculation
of Cd using the slope from your experimental graphs.
Cover Memo
Write a Professional Format Memo to your instructor addressing the following issues:
1. Provide a table summarizing your average experimental and theoretical (Calculate/Read
Figure 12.28) Cd, average Cw, and Cw & Cd from the graphs.
3. Based on how well or poorly the constrained lines fit the data, what do you conclude
about the accuracy and usefulness of the theoretical equation shown in class? Tell how you
judged the “goodness of fit�
4.
Compare the point gage data and the manometer data. Describe any differences and
explain why they are there.
5.
Compare your vented and triangular Cd values with values generated by the empirical
equations presented in the class handout (i.e., by Daughtery, Lenz). Discuss any reasons for
discrepancies.
Submittal
Digital copy of spreadsheet to Canvas (assignment drop box)
Label and order your lab report as shown below.
Memo: Answering all the above questions with intro, conclusions.
Figure 1: Plot of flow against H3/2 for the rectangular weir (both point gage and
manometer) and H5/2 for the triangular weir (one graph).
Figure 2: Qtheoretical against Qmeasured
Attachment: Hand calculations (neat and labeled)
FLOW OVER A WEIR
CE 130L
Experiment IV
Introduction
• Weir
•
A weir is a notch of regular form through which water
flows
• For example: depression in the side of a tank,
reservoir channel, or it may be an overflow dam or
other similar structure
• Weirs are elevated structures in open channels that
are used to measure flow and/or control outflow
elevations from basins and channels.
Introduction (cont’d)
• The edge or surface over which the
water flows is called the crest of the weir
• The overflowing sheet of water is termed
the nappe
• The depth of water producing the
discharge is the head
Introduction (cont’d)
• Types of Weir
• Sharp Crested
• Broad crested
Introduction (cont’d)
• Weir Shapes
• Sharp or Broad Crested
• Rectangular
• Contracted
• Suppressed
• Triangular
• Trapezoidal
• Parabolic
Rectangular
Triangular or V-notch
Triangular or V-notch
Trapezoidal
Introduction (cont’d)
• Weir flow types:
• Free discharge
• nappe discharges into the air
• Submerged discharge
• discharge is partially under water
Objectives
• Become familiar with weirs as a measurement device
• Principles
• Applications
• Become aware of the methods for their calibration
• Determine the discharge coefficients
Theory
• Assumptions:
• Velocity distributions upstream from weir is uniform
• All fluid particles move horizontally as they pass the weir crest
• Pressure in the nappe is zero
• Influence of viscosity, turbulence, secondary flows, and surface
tension may be neglected
Theory (cont’d)
Rectangular Weir
2
Qtheory = L 2 g H 3 / 2
3
Qactual = C w H
3/ 2
2
C w = Cd L 2 g
3
Qactual = Cd Qtheory
2
Qactual = Cd L 2 g H 3 / 2
3
C w :Weir Coefficient
Cd :Discharge Coefficient
Theory (cont’d)
Effective Crest Length
L < b (nappe with end
contractions)
b = width of the channel (m)
L = length of the crest (m)
Le = effective length of the crest
(m)
n = number of end contractions
H = head above the crest (m)
Le = L − 0.1nH
2
3/ 2
Qactual = Cd Qtheory = Cd Le 2 g H
3
Theory (cont’d)
Triangular Weir
8
ï± 5/ 2
Qtheory =
2 g tan H
15
2
Qactual = Cw H 5 / 2
8
ï±
C w = Cd
2 g tan
15
2
Qactual = Cd Qtheory
8
ï± 5/ 2
Qactual = Cd
2 g tan H
15
2
Theory (cont’d)
Weir Coefficient of Discharge
Qactual
Cd =
Qtheory
Cw
2
= Cd
L 2g
3
8
ï±
C w = Cd
2 g tan
15
2
V-Notch Weir Cd
Procedures
1.
Refer to lab procedures
Point Gages
Data
Rectangular Weir
Run No.
Flow meter
(GPM)
Point Gage
(ft)
Manometer
(in)
V-Notch
Point Gage
(ft)
1
2
3
4
5
6
7
8
9
10
Rectangular
Rectangular Zero Manometer=
Rectangular Zero Point gage=
Width
Concrete Zero Point gage=
Height
V-Notch
Results and Analysis (cont’d)
• Refer to Lab Manual
Zero
Point Gage Rec.
Zero
Manomete
Rec.
Gravity
(ft/s2)
Rectangular Weir Height
Point Gage(ft)
Rectangular Weir
Height Mano.
V-Notch Weir Height
(ft)
0,896
0,5
32,2
2,121
15
0,795
Run
Flow Meter
(gpm)
Q Measured
(cfs)
214
250
281
311
340
370
156
88
0,477
0,557
0,626
0,693
0,758
0,824
0,348
0,196
Rectangular Weir
1
2
3
4
5
6
7
8
9
10
Point Gage
(ft)
2,339
2,357
2,373
2,389
2,401
2,412
2,305
2,262
Manometer (in)
17,700
17,900
18,150
18,350
18,400
18,550
17,300
16,800
Rectangular Weir Manometer
Q Theory Calc (cfs)
0,931
1,036
1,173
1,286
1,315
1,403
0,732
0,507
0,000
Discharge
Weir
Coefficient Coefficient
Cd
Cw
0,512
4,468
0,538
4,689
0,534
4,655
0,539
4,698
0,576
5,023
0,588
5,124
0,475
4,142
0,387
3,375
Manometer Cd Theo
0,634
0,634
0,634
0,635
0,635
0,635
0,634
0,636
Head
Point gage
(ft)
0,218
0,236
0,252
0,268
0,280
0,291
0,184
0,141
Rectangular Weir Point Gage
Q Theory Calc (cfs)
0,888
1,000
1,103
1,210
1,292
1,369
0,688
0,462
Discharge Coefficient
Cd
0,537
0,557
0,568
0,573
0,586
0,602
0,505
0,425
Average
0,519
4,522
0,635
1,001
0,544
V-Notch Weir Point Gage
Run
1
2
3
4
5
6
7
8
9
10
Flow Meter
(gpm)
214
250
281
311
340
370
156
88
0,477
0,557
0,626
0,693
0,758
0,824
0,348
0,196
Point Gage
(ft)
Head (ft)
1,305
1,330
1,358
1,381
1,401
1,416
1,246
1,165
0,510
0,535
0,563
0,586
0,606
0,621
0,451
0,370
Average
H^5/2
0,186
0,209
0,238
0,263
0,286
0,304
0,137
0,083
Average
V-Notch Weir Angle
Rect . Weir Length
V-Notch Weir Angle(rad)
90 inches
19,56
1,571
Head
Manometer
(ft)
0,225
0,242
0,263
0,279
0,283
0,296
0,192
0,150
(Head (ft)
Point gage)^3/2
0,102
0,115
0,127
0,139
0,148
0,157
0,079
0,053
Rectangular Weir
Rectangular Weir Point Gage
Weir Coefficient Cw
2,874
2,981
3,036
3,064
3,137
3,222
2,702
2,272
Point Gauge Cd Theo
0,723
0,730
0,737
0,744
0,749
0,753
0,710
0,695
(Head (ft)
Manometer)^3/2
0,107
0,119
0,134
0,148
0,151
0,161
0,084
0,058
2,911
0,730
V-Notch Weir Point Gage
Q Theory Calc (cfs)
Discharge Coefficient
Cd
Weir Coefficient
Cw
5,39
5,50
5,61
5,71
5,79
5,85
5,15
4,82
0,088
0,101
0,112
0,121
0,131
0,141
0,067
0,041
4,447
5,100
5,617
6,115
6,593
7,103
3,393
2,046
5,052
0,100
5,052
Cd from
Fig 12.28
#DIV/0!
Avg. Exp. Discharge Coefficient Cd
Avg. Theo. Discharge Coefficient Cd
Avg. Graph Discharge Coefficient Cd
Avg. Exp. Weir Coefficient Cw
Avg. Graph Weir Coefficient Cw
Rectangular (Manometer) Rectangular (Point Gauge)
0,519
0,544
V-notched
0,100
0,635
0,730
#DIV/0!
4,522
2,911
5,052
Figure 1 : H3/2 or H5/2 vs. Qmeasured
0,900
0,800
0,700
0,600
y = 5,0252x
R² = 0,9988
y = 2,6539x
R² = 0,9998
y = 4,8287x
R² = 0,9978
Qmeas. (cfs)
0,500
0,400
0,300
Point Gauge Weir Coeff. Cw
Manometer Weir Coeff. Cw
0,200
Point Gauge V-notch Weir Coeff. Cw
0,100
0,000
0,000
0,050
0,100
0,150
0,200
H^(3/2) (ft) or H^(5/2)
0,250
0,300
0,350
Figure 2: Qtheoretical vs. Qmeasured
1,000
Rec Weir Point Gage
y = 0,6001x - 2,7269
R² = 0,9855
Rec Weir Manometer
Triangular Weir
Linear (Rec Weir Point Gage)
y = 0,7078x - 0,1869
y = 0,7076x - 0,1533
R² = 0,9773
R² = 0,9975
Linear ( Rec Weir Manometer)
Linear (Triangular Weir)
0,500
0,000
0,000
1,000
2,000
3,000
4,000
Qtheor. (cfs)
5,000
6,000
7,000
Cover Memo
Write a Professional Format Memo to your instructor addressing the following issues:
1. Provide a table summarizing your average experimental and theoretical (Calculate/Read
Figure 12.28) Cd, average Cw, and Cw & Cd from the graphs.
3. Based on how well or poorly the constrained lines fit the data, what do you conclude about
the accuracy and usefulness of the theoretical equation shown in class? Tell how you judged
the “goodness of fit�
4. Compare the point gage data and the manometer data. Describe any differences and explain
why they are there.
5. Compare your vented and triangular Cd values with values generated by the empirical
equations presented in the class handout (i.e., by Daughtery, Lenz). Discuss any reasons for
discrepancies.
Cd from Fig
12.28
0.584
0.586
0.585
0.586
0.584
0.585
0.587
0.588
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