Homework answers / question archive / ENV5104 S1 2023 – Report 3   • Analyse the behaviour of coastal waves and currents and interactions with hydraulic structures; • Apply hydraulic principles to evaluate the process of sediment erosion, transport, deposition and river morphology; • Apply hydraulic theory to evaluate pipeline flow and design pumped pipeline systems; • Evaluate and mitigate the impacts of pressure transients in pipeline systems; • Undertake hydraulic analysis and employ hydraulic modelling principles to water flow and distribution systems

ENV5104 S1 2023 – Report 3   • Analyse the behaviour of coastal waves and currents and interactions with hydraulic structures; • Apply hydraulic principles to evaluate the process of sediment erosion, transport, deposition and river morphology; • Apply hydraulic theory to evaluate pipeline flow and design pumped pipeline systems; • Evaluate and mitigate the impacts of pressure transients in pipeline systems; • Undertake hydraulic analysis and employ hydraulic modelling principles to water flow and distribution systems

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ENV5104 S1 2023 – Report 3

 

• Analyse the behaviour of coastal waves and currents and interactions with hydraulic structures;

• Apply hydraulic principles to evaluate the process of sediment erosion, transport, deposition and river morphology;

• Apply hydraulic theory to evaluate pipeline flow and design pumped pipeline systems;

• Evaluate and mitigate the impacts of pressure transients in pipeline systems;

• Undertake hydraulic analysis and employ hydraulic modelling principles to water flow and distribution systems. Rationale This assignment is based on the material covered in Modules 5, 9, 10, 11 Important Information This is an individual task where you must complete the work yourself and must acknowledge all sources of information using appropriate referencing where required. Before starting please review the USQ’s Academic Integrity Policy https://policy.usq.edu.au/documents/13752PL “The University considers behaviour by Students, which does not uphold the principles of Academic Integrity and honesty and that misrepresents their academic achievement, to be Academic Misconduct.” For guidance on what constitutes Academic Misconduct and its various categories, at USQ refer to the USQ Student Academic Misconduct Policy available at: https://policy.usq.edu.au/documents/14132PL By submitting this assignment you hereby certify that: The submission is entirely my own work except where due acknowledgement is made in the text and that no part has been copied from any other person’s work. Special Instructions All sources should be properly referenced using the Harvard referencing style. The Harvard (AGPS) style to be used is defined by the USQ Library referencing guide http://www.usq.edu.au/library/referencing. Instructions for Submission The assignment is to be submitted electronically via study desk. The link is available on assessment tab on the course studydesk.

• The reports for Task 1 and 2 should contain an explanation of the methods and copies of all results (plots).

• Submit copies of your spreadsheets or code for Task 1

• Submit a zip file containing the HECRAS files for Task 2

• Task 3 must be produced using a word processor and submitted as a separate word file.

 

Late Submissions (USQ Assessment Procedure) “Assessment Items submitted after the published due date without an approved extension or submitted after the revised due date where an extension has been granted, will incur a penalty of 5% of the available Mark, per Calendar Day late”. “Assessment Items submitted more than 10 Calendar Days after the published due date without an approved extension, or more than 10 Calendar Days after the revised due date where an extension has been granted, will receive a Mark of zero”

Assessment Tasks This assignment is comprised of three tasks:

 

Task 1 – Unsteady Pipeline flow 70 marks

Task 2 – Unsteady Open Channel Flow 200 marks

Task 3 – Ocean & Coastal Engineering 130 marks

 

Task 1 – Unsteady Pipe flow

You have been tasked to design a system to mitigate the risk of water hammer and surge within a large water pipeline identical to Tutorial problem 9.2. o Pipeline diameter 2.5m o Design flow 29.452 m3 /s. Velocity of 6 m/s (Q has been modified to simplify question) o Head at downstream end of pipeline is 0 m at design flow o Head at downstream end of pipeline is 20m at zero flow Neglecting the elasticity of the pipeline, a complete and sudden closure in less than 2.7 seconds would result in a water hammer surge in excess of 8 MPa likely posing a significant safety issues. There are two options for this system: A. A Surge tank 10m internal diameter (Fs = 1.5) B. A valve which will be carefully controlled such that the valve is maintained at a maximum valve pressure (HV) of 20 + 2N metres Where N is the last digit of your student number. e.g. if your student number is 0061261309 your maximum have pressure is: HV = 20 + 2 x 9 = 38m For simplicity you may assume that the friction f remains constant and does not vary with Reynolds number Your Tasks: 1. Complete Tutorial question 9.2 with the slightly modified flow of 29.452 m3 /s using a spreadsheet or matlab script. 2. Provide plots of the pipe velocity and depth in the surge chamber (which is equal to the head at the valve) over a period of 300 seconds. 3. Complete calculations for option B, a valve which carefully closes over a period of time. You should use a delta V of 0.1 or 0.2 m/s 4. Plot the results for option B including pipe velocity and valve opening % over time. 5. Compare the results between option A and B and make a conclusion over which one you believe would be most appropriate and why. Note that both are valid options in this case, it is up to you to make your own decision based on your results

 

Task 2 – Unsteady Open Channel Flow

In this task you will be utilising HECRAS to study the behaviour of a channel under both steady and unsteady flow. The channel is straight and trapezoidal in shape and surrounded by a grassed area with a total width of 30m. The channel of interest is 6km long (6000m) and has a cross section as shown in the table below: Manning n values: Channel n = 0.018 ROB & LOB n = 0.035 Slope: (0m is station 1 at Downstream end) Bed Slope 0m – 3000m 0.0005 Bed Slope 3000m – 6000m 0.002 The slope of the channel varies along its length as shown below. At the 3000m position down the channel the slope decreases from 0.002 (2m per km) to 0.0005 (0.5m per km). This can be replicated by positioning a cross section at the 3000m position and varying the elevation at each of the stations accordingly. 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 0 1000 2000 3000 4000 5000 6000 Elevation (m) Distance from Station 1 (m) Bed Bank Station (m) Elevation (m) 0 2.0 0.1 1.5 10 1.5 Left Bank 13 0 17 0 20 1.5 Right Bank 29.9 1.5 30 2.0 Model Configuration & Simulation conditions • Maximum distance between cross sections or interpolated cross sections is 200m • Upstream Boundary: flow hydrograph (given below) • Downstream Boundary: normal flow with friction slope equal to 0.0005 (bed slope at station 1) • Computation interval: 1 minute • Hydrograph interval: 1 minute • Detailed Output Interval: 5 minute Inflow hydrograph (at 6000m) The channel is subject to a continuous base flow of 3m3 /s you are tasked with modelling the response of the channel to an unsteady inflow with a duration of 5 hours. The hydrograph is represented by a flowrate in cumecs measured at 10 minute intervals. Time flow (m3 /s) Time flow (m3 /s) Time flow (m3 /s) 0:00 3 2:00 17.4 4:00 3 0:10 6.5 2:10 18.8 4:10 3 0:20 9.2 2:20 15.7 4:20 3 0:30 13.6 2:30 13.2 4:30 3 0:40 15.4 2:40 8.4 4:40 3 0:50 18.7 2:50 6.3 4:50 3 1:00 20 3:00 3 5:00 3 1:10 17.3 3:10 3 1:20 14.4 3:20 3 1:30 10.8 3:30 3 1:40 7.5 3:40 3 1:50 12.6 3:50 3 Submission Along with your report you must submit a zip file containing the relevant HECRAS files. These files may be used to check your results or to provide part marks if your results are incorrect. Your Tasks: 1. Set up a model within HECRAS that represents the given channel dimensions and slope. 2. Pick a flowrate (between 1-5 cumecs) and use hand calculations to determine the normal flow depth and specific energy for one of the channel slopes. Model this steady flowrate in HECRAS and compare with your manual calculation. 3. Model the given hydrograph in HECRAS and provide results for: a. The stage (elevation) and flow hydrographs for the upstream and downstream ends of the channel b. Plots of the profile (water and channel elevation over length) for at 3 different times during the simulation on the same set of axes: i. Start time (0:00) ii. Time of max inflow (1:00) iii. Time of max outflow (?) (Hint: you can copy values to the clipboard using File->Copy Values to Clipboard) c. General profile plot of hydraulic depth for the same times as for part b d. Two examples of the cross section plot, one where the water level is lower than the bank height (1.5) and one where it has exceed the channel banks. Clearly state the location and time where these cross sections are taken. 4. It is likely that the channel overtops over part or all of its length when subjected to the provided hydrograph. Please contact examiner if your channel does not overtop. Propose a modified channel cross section that should accommodate the given flow over the entire length of the channel. You are permitted to change either the entire channel length or part of the channel that overtops. Clearly describe your new cross section. 5. Model this new cross section and provide the results for a. The stage (elevation) and flow hydrographs for the upstream and downstream ends of the channel (and compare with 3.a) b. General profile plot of hydraulic depth for any time of your choosing from part 3.c above. Compare these results with the original design 6. Provide sufficient outputs to demonstrate that water does not overtop the banks of the channel when this new cross section is subjected to this same inflow. 7. General discussion and a reflection on your own personal experience in using the model for this assignment. 8. Write up this question in a report format. You must submit a word document.

Marking Scheme Mark HECRAS Model of existing channel - HECRAS correctly configured according to given specifications - Explain the configuration of HECRAS in report - HECRAS files must be included 20 Validation of Steady Flow - Determine water depth and specific energy for one of the slopes - Model steady flow in HECRAS - Compare results between manual and model 20 Model results for given hydrograph a) Stage and flow hydrographs for upstream and downstream ends b) Plots of profile at 3 times during the simulation c) Plot of hydraulic depth for these 4 times d) Plots of cross section (as specified in 3.d) 40 Discussion of results Discussion relating to: a) The routing of the hydrograph b) Profile plots at the 3 times c) Hydraulic depth at the 3 times d) Cross section plots You Are strongly encouraged to combine the discussion with the results by discussing each plot/graph as it is presented in your report. These have been split to show the importance of your discussion. 20 New channel design that does not overtop - New design identified - Explain how the design is different from the original shape - Modelled this design in HECRAS - Provide a separate set of HECRAS files for this design 20 Model results for new design - Stage and flow hydrographs for upstream end - Compare stage and flow with results from 3.a - General profile plot of hydraulic depth (5.b) 30 Proof that new channel does not overtop - Comparison of this profile with result from original channel - Sufficient results presented to demonstrate the channel does not exceed the level of the channel banks - Discussion 20 Reflection - General discussion on the model - Your personal reflection on use of the model 20 Report Presentation - Introduction - Report format - Conclusion 10 200

Task 3 – Ocean and Coastal Engineering

Select a specific topic area related to hydraulics in ocean and coastal environments that is of interest to you. Ideally your chosen topic should have direct relevance to the design or construction of engineering structures subjected to the impacts of tidal flows, waves and coastal erosion. You should review the marking rubric before deciding on your proposed topic. Conduct a literature review on this topic which should include: • Introduction • Importance of the topic to engineers o Justification as to why this topic is of relevance (economic/social/environmental) • Hydraulic theory relating to the topic. • How this theory might/should inform engineering design. • Case study of location where the topic is of relevance. o This may be an existing project or a planned development. • Recent developments and current research (e.g. new theories, new engineering solutions, areas which require further research) • Conclusion and Reflection This review should contain approx. 1,000 - 1,500 words excluding references. It is important that you use scholarly articles (i.e. peer reviewed journal papers) in this review. The hydraulic theory mentioned above may include content already covered in the course and/or related theory that you may find during your literature review. Marks are awarded for how you are able to explain the relevance of the theory and not for the complexity of that theory. You are welcome to include any images, figures or tables that are relevant but these must be properly referenced. The words in this review must be entirely your own, plagiarism and use of AI writing tools are not permitted according to UniSQ Academic Integrity policies. This file must be submitted as a separate word file. (not pdf) Task 3 – Ocean and Coastal Engineering Very Poor Poor Satisfactory Proficient Exceptional Marks Intro to the topic and discussion of the Importance Poor attempt (0-2) Inadequate introduction to the topic (3-9) Satisfactory attempt to introduce the topic and explain its importance. (10-12) Detailed introduction to the topic and its relevance to engineering design. (13-16) Clear and informative introduction to the chosen topic. Comprehensive discussion about the importance of including economic, social & environmental impacts if relevant. (17-20) /20 Hydraulic Theory Failed attempt to link the topic to hydraulic theory. (0-2) Inadequate or unclear linkage to hydraulic theory (3-9) Satisfactory explanation of how the topic can be understood using hydraulic theory (10-12) Clear and concisely introduced relevant hydraulic theory that relates directly to the topic (13-16) Comprehensive introduction to relevant hydraulic concepts and theory relating to the topic. Discussions on limitations/assumptions of this theory (17-20) /20 Impacts on Engineering Design Poor attempt (0-2) Inadequate discussion on the impacts (3-9) Satisfactory attempt to link the theory to some aspect of the engineering process (10-12) Example(s) presented of how the theory does or should inform engineering design. (13-16) Clear examples of how the hydraulic theory influences engineering design or selection of suitable sites or conditions. (17-20) /20 Case Study of existing or proposed project Poor attempt (0-2) Relevant case study but not adequately linked to topic (3-9) Satisfactory discussion of a case study linked to the topic. (10-12) Critical review of the case study with mention on possible or realised benefits (13-16) Insightful summary of the case study. Discussion on the benefits of the project and issues faced (if any) (17-20) /20 Recent Developments and Research Poor attempt (0-2) Limited discussion of available research. (3-9) Paraphrased a small number of relevant sources (10-12) Critical review of relevant literature (13-16) Insightful review of relevant literature and identification of one or more key gaps for future research of or development (17-20) /20 Reflection & Conclusion Poor attempt (0-3) Some attempt to write a conclusion (3-9) Satisfactory conclusion linking to parts of the report. (10-12) Good conclusion linking to most of the key and some mention of your learnings. (13-16) Concise conclusion summarising the key messages throughout report and a reflection on your learnings. (17-20) /20 Referencing Poor attempt at referencing (0-1) Some attempt at referencing (2-4) In text referencing used to support some arguments (5) Reference list in Harvard style, most ideas properly referenced (6-8) Reference list correctly formatted using Harvard style. All arguments properly referenced in text (9-10) /10