6HX509 Civil Engineering Hydraulics | My Assignment Tutor -

CW V.41 Programme:BSc (Hons) Engineering (Civil) Top UpUnit Code/Title6HX509 Civil Engineering HydraulicsUnit Credits/ levelCredits 20 QCF LEVEL: 6Tutor:V.OkeInternal VerifierA.Janbey Academic year2020/2021IndividualGroupAssessmentNumberRetake Issue date: May 2020Submission deadline: TBAThe aim of this assignment is to demonstrate the students’ ability to produce a technicalengineering report investigating steady fluid flow phenomena in open channels, using bothlaboratory experiments and computer simulations. As such, the assignment comprises twocomponents: Part A. It is concerned with laboratory investigation of two methods of measuringopen channel flow and hydraulic jumps.o A.1. Crump weir [25marks]o A.2. Broad crested weir [10marks] Part B. It involves a computer model of gradually varied flow in an open channel (M2backwater profile). [15marks]Part AThis part investigates the phenomenon of rapidly varied steady flow in an open channel. Thiswill be based on a laboratory experiment comparing the measurement of flow using a crumpINTERNAL VERIFICATIONAssignment Brief TemplateFORM D1CW V.42weir with that using a broad crested weir, and will also investigate hydraulic jumpsoccurring downstream from the two weirs, and matching the experimental results obtainedfrom those from theory. Estimates will also be made of the loss of specific energy of the flowover the two weirs. The experimental procedures and required analyses are outlined below:A.1. Crump Weir[Total marks: 25]Experimental Procedure.1. Verify that the hydraulic bench unit (water tank and pump) has enough water and isconnected to the H23 flume water intake.2. Measure the channel dimensions (width and depth), and ensure that the slope (So) ofthe flume is cero (So=0%),3. Install the crump weir at about 800mm downstream from the point at which thewater leaves the stilling filter.4. Turn on the pump of the hydraulic bench, and adjust the flow to its maximum byopening the valve. The water should not overflow from the channel.5. Obtain the depth of the flow at the following locations by using the depth gaugeprovided. The depth is the result of the difference of two readings: bottom bed andwater surface.a. Some 100mm upstream of the weir (y1)b. At the lowest depth at the bottom of the weir (y2)c. Just before the jump (y3)d. After the jump where the water is in tranquil flow (y4)6. Estimate the length of the jump (L), i.e. the distance between y3 and y4.7. By using the Pitot tube measure the velocity head (if possible) at the same fourlocations, comment on any difficulties experienced.8. Measure the flow rate by using the volume gauges built into the hydraulic bench, andthe stop watch provided. It is suggested to record the time that takes to deliver 5 litresof water.Please note that the tank starts filling when the plug (rubber ball) is blocking theoutlet.In order to reduce the uncertainty and improve the results, measure the flow rate atleast 3 times and obtain an average.Calculate the mean flow in m3s-1CW V.439. Decrease the flow rate by closing slightly the valve and repeat the procedure frompoint 5. Verify that the depth upstream of the weir decreases at least 5 mm. Andrepeat this procedure at least 5 times more, every time with a different discharge.Calculation Procedurea- For the very first value of volumetric flow rate ( , calculate the critical depth ( ) andcritical energy ( ).[2 marks]b- Using that value of volumetric flow rate per unit width ( ), evaluate the specific energy fora range of theoretical depths up to a maximum of 200 mm. Plot these values in adimensionless form: ( ) versus ( ). On the same curve, plot the values of the andcalculated from the measured and in dimensionless form, for the same discharge. Explain how the graph has been generated and investigate the phenomenon ofrapidly varied steady flow in an open channel along with the characteristics ofa free hydraulic jump.[2 marks] Briefly list the equipment used.[1 mark ] Experimental set up.[1 mark ] Tabulated results.[2 marks] Raw measurement[in appendix] Fully annotated plots and description of it.[2 marks]c- Now using the whole 5 experimental results; calculate the ratio , and the Froudenumber just before the jump in each case. Using this calculated , calculate thetheoretical value of . Plot against for both experimental and theoreticalCW V.44results. For fully annotated plots and description of it, including equation for Froudenumber.[4 marks]d- Discuss your results, assessing their validity and reliability, comment on the accuracy anddraw the relevant conclusions.[2marks] How valid the equations.[2 marks] What were the assumptions for the equations when derived, what human and laberrors were present, accuracy of instruments used etc.[2 marks] Draw conclusions.[2 marks] For wider implications.[1 mark]e- For each case, calculate the flow force across the gate, the head loss across the jump.[2 marks]A.2. Broad Crested WeirRepeat the procedures outlined in A.1 using the broad crested weir in the same position asthe crump weir was.[Total marks: 10]a. Calculate the loss of specific energy across each weir and through each hydraulic jump.[3 marks]b. Calculate the Drag Coefficient of the weir[3 marks]c. In your conclusion compare the performance of the two weirs as measuring systems forthe flow in open channels and discuss this with reference to published work on eachweir.[2 marks]d. Suggest which weir would be used if you needed an accurate measure of irrigation waterdelivered to an area or a large agricultural business[1 mark]CW V.45e. Comment on the use of hydraulic jumps to reduce the energy in open channel flows.[1 mark]Part B. Gradually Varied Flow SimulationThis part requires you to produce a “simple computer model” (using EXCEL) to establishwater level profiles in a proposed channel (delivery canal to a reservoir, terminating with afree outfall) using the direct step method.[Total marks: 15]The channel, rectangular in cross-section, with a width b=3.0m, is required to carry aminimum discharge (Q) of 2.50 m3/s. The channel has a bed slope, , constructedat a minimum elevation of 100.0m above Ordnance Datum (OD) at the downstream end ofthe channel. The channel bed surface is earth with gravel, having a Manning’s friction factor,.If the critical depth (ycr) is assumed at the outfall (x=0), obtain the minimum length that thechannel needs upstream to attain the normal depth (yn). Use the direct step method todetermine the water level profile along the channel (backwater curve), assuming graduallyvaried flow. It is recommended to use Δy=0.010m.Plot this profile to scale. You will need to illustrate two calculations steps in your report, andthen use a spreadsheet (e.g. MS Excel) to obtain the full flow profile.GVF Direct Step Method1. Identify the condition of the flow2. Identify the type of transition and subsequently the corresponding profile3. Identify the control depth, and determine if the calculations go upstream ordownstream from control section, setting that point as chainage x=04. Assume a depth increment (Δy).CW V.465. Determine the geometrical characteristics of two consecutives cross sections (controldepth and the control depth with the increment): hydraulic area (A), wetted perimeter(P) and hydraulic radius (R)6. Determine the velocity (V2/2g) and the total energy head (E) of the section.7. Determine the friction slope (Sf):8. Calculate the energy head increment (ΔE) between consecutives sections.9. Find the mean friction slope value:10. Find the horizontal increment (Δx) from11. Accumulate Δx as12. Determine the bed and water surface levels:Bed level =Water surface level =13. Repeat the process from step 5, until Sf mean=0 or until it changes its signalFill the table below with the results obtained from the procedure suggested above.h A=b*h P=b+2h R=A/P R^(4/3) V=Q/A v^2/2g E=h+y^2/2g Fr ΔE Sf = v^2 n^2 / R^1.33 Sfmean=(Sf i + Sf i+1)/2 S0 -Sf mean Δx x = Σ (Δx) BED Level Water Surface Levela) Description of how the spreadsheet was constructed[3 marks]b) Show two calculation steps[2 marks]c) The actual spreadsheet of the rectangular channel[4 marks]d) Plot the variation of the water surface and bed level with respect to the length, startingat the outfall (x=0)[3 marks]e) Final answer on length[3 marks]END OF BRIEF