wk1_Introduction.pdf
- 1. Planning and Design of Hydraulic Structures and Hydropower WRM-32 Teaching team Assist. Prof Rohullah Malikzooi rohullah.malikzooi@kpu.edu.af Assist. Prof Hamidullah Turabi en.hamid.t@kpu.edu.af Dr Dominic E.L. Ong d.ong@griffith.edu.au Prof. Hong Zhang hong.Zhang@griffith.edu.au Kabul Polytechnic University
- 2. Upon completion of this course, students should: • Understand design procedure of hydraulic structures • Familiarize with maintenance of hydraulic structures and hydropower • Familiarize with the layout of micro-hydropower Objectives
- 3. After the completion of this course, the students will be able to: 1. Describe several types of earth and concrete dams and hydraulic structures. 2. Describe design procedures for earth dams. 3. Explain the design procedure for concrete dams. 4. Know parts of earth and concrete dams. 5. Detail design procedures for earth dams. 6. Describe the design procedure for concrete dams. 7. Impact of climate change on hydraulic structures. 8. Maintenance of hydraulic structures. 9. Safety of dam 10. Describe spillways and hydraulic gates. Achievements
- 4. Assessment Task Due Date Weighting Group presentation Throughout the semester 20% Individual Assignment Week 8 20% Final Exam Week 17 60% Assessments Assist. Prof Rohullah Malikzooi will provide more details.
- 5. Your expertise and experience in hydraulic structures Design engineers Engineering service Water resources/ hydrology GIS/ Data management Managers/ directors Water quality Water allocation Surface water /canal
- 6. Introduction to Hydraulic Structures Prof Hong Zhang School of Engineering & Built Environment Griffith University, Australia hong.zhang@griffith.edu.au P. Novak, A.I.B. Moffat, C. Nalluri and R. Narayanan, Hydraulic Structures, 4th Edition, 2007, Taylor & Francis Sheng-Hong Chen, Hydraulic Structures, 2015, Springer C S James, Hydraulic Structures, 2020, Springer YouTube, uploaded by: CIMICGroup, Hindze Dam, Gold Coast, Australia
- 7. • Hydraulics is a subset of ‘Fluid Mechanics’ where the focus is on liquids (especially water) in pipes, lakes, rivers and open channels. Uses the theory for ‘incompressible’ fluids. • Fluid Mechanics is the science that deals with the action of forces on fluids ✓ Fluids at rest – Hydrostatics ✓ Fluids in motion – Kinematics, Fluid dynamics • An incompressible fluid is a fluid, the density of which remains constant during flow. Liquids are normally treated as being incompressible, as a gas can be when only slight pressure variation occurs. What is ‘Hydraulics’? http://worldrivers.net/2020/03/31/sediment-transport/
- 8. Basic types of free surface flow (James, 2020) (GV) (RV)
- 9. • steady -> all the time derivatives of a flow field vanish • unsteady (transient) -> some time derivatives ≠ 0, e.g. Steady and Unsteady Flow 𝜕𝑄 𝜕𝑡 = 0 𝜕ℎ 𝜕𝑡 = 0 𝜕𝑄 𝜕𝑡 ≠ 0 𝜕ℎ 𝜕𝑡 ≠ 0 Q - discharge rate, h – water level h Q http://stream1.cmatc.cn/pub/comet/HydrologyFlooding/streamflow/comet/hydro/basic/
- 10. Open Channels 10 Free surface is the hydraulic grade line • Steady flow over a spillway of constant width, where the waterflow progressively faster as it goes over the brink of the spillway (from A to B), caused by the suddenly steeper slope. The faster velocity requires a smaller depth, in accordance with conservation of mass (continuity). • From reach B to C, the flow is uniform because the velocity, and thus depth, are constant. • After reach C the abrupt flattening of channel slope requires the velocity to suddenly, and turbulently, slow down. Thus there is a deeper depth downstream of C than in reach B to C.
- 11. Flow under a sluice gate Two different depths for the same discharge
- 12. • Common examples of unsteady open channel flows include flood flows in rivers and tidal flows in estuaries, irrigation channels, headrace and tailrace channel of hydropower plants, navigation canals, stormwater systems and spillway operation. Unsteady open channel flows https://www.couriermail.com.au/news/wivenhoe-dam-gates- opened-wider-to-increase-flows-into-brisbane-river/news- story/f5150989e4093ccc284640d5e7bae3e6?sv=4d8b3bb91bdd5e c0005419cc1e11e160 2011 flood, Wivenhoe Dam release reached 12,000 m3/s https://queenslandplaces.com.au/exhibit/digital- image/dscf1100 Brisbane River in flood, January 2011 In unsteady open channel flows, the velocities and water depths change with time and longitudinal position. For one-dimensional applications, the relevant flow parameters (e.g. V and h) are functions of time and longitudinal distance.
- 13. 𝐹𝑟 = 𝑉 𝑔𝑦 Froude Number, Fr The Froude number is the ratio of inertial force to gravity force 𝐹𝑟 = 𝑞 𝑦𝑐 𝑔𝑦𝑐 = 1 For rectangular cross section! Critical Flow For non-rectangular cross section y in the Froude No. is replaced by the hydraulic depth (Dc) c F D g V N = T A Dc =
- 14. Froude number 𝐹𝑟 = 𝑉 𝐶 = 𝑉 𝑔 𝐴 𝐵 = 𝑉 𝑔ℎ (for a rectangular channel) • v - flow velocity ➢ shallow water flow: average flow velocity • c - water wave propagation velocity ➢ shallow water wave: cross-sectional area A, free-surface width B Subcritical or Supercritical Flow Standing water Subcritical discharge Critical discharge Supercritical discharge v = 0 Fr = 0 v < c Fr < 1 v = c Fr = 1 v > c Fr > 1
- 15. 2 2 2gy q y E + = Solution to the Specific Energy Equation Two Possible Depths, y Minimum Specific Energy, Emin Critical Depth, yc
- 17. Bernoulli equation 2 2 2 3 3 1 1 2 2 1 2 3 2 2 2 p v p v p v z z z g g g + + = + + = + + Streamline along the centreline Datum, z = 0 g V 2 head Velocity 2 = z p + = head c Piezometri Also: hydraulic head
- 18. ◼ The flow has to be steady , ◼ The fluid is incompressible (water is usually assumed to be incompressible) ◼ The fluid flow is inviscid (= frictionless flow) Restrictions of the Bernoulli Equation A fluid which has no viscosity; it therefore can support no shearing stress, and flows without energy dissipation. Also known as ideal fluid; nonviscous fluid; perfect fluid. 𝜕𝑉 𝜕𝑡 = 0
- 19. • The flow can be described at any location and any time by 2 variables, flow velocity (V) or the water discharge (Q), and the water depth (h). • The unsteady flow can be described by 2 equations: the conservation of mass and the conservation of momentum. Basic equations www.researchgate.net/figure/Illustration-of-general- 1D-model-of-the-river-channel-integrated-with-a-2D- model-of-the_fig1_314486865/download www.usgs.gov/media/images/diagram-channel- cross-section-subsections
- 20. The forces acting on the control volume contained between Sections 1 and 2 include: • the pressure forces at sections 1 and 2 (the pressure force components on the channel sidewalls if the channel width vary in the x- direction) • the weight of the control volume • the reaction force of the bed (equal, in magnitude, to the weight in absence of vertical fluid motion) • the flow resistance opposing fluid motion 𝑄 + 𝜕𝑄 𝜕𝑥 ∙ 𝑑𝑥 R
- 21. 𝑄 + 𝜕𝑄 𝜕𝑥 ∙ 𝑑𝑥 Continuity Equation 𝜌 ∙ 𝑄 ∙ ∆𝑡 − 𝜌 ∙ 𝑄 + 𝜕𝑄 𝜕𝑥 ∙ 𝑑𝑥 ∙ ∆𝑡 = 𝜌 ∙ ∆𝐴 ∙ 𝑑𝑥 + 𝜌 ∙ 𝑞𝑠 ∙ 𝑑𝑥 Mass flux into control volume (t1 to t2, ) Mass flux out control volume (t1 to t2) Increase of mass inside control volume (t1 to t2) 𝝏𝑨 𝝏𝒕 + 𝝏𝑸 𝝏𝒙 = 𝒒𝒔
- 22. Momentum = Mass per unit length * velocity 𝑀 = 𝜌 ∙ 𝑄 ∙ 𝑑𝑥 Momentum Flux = Momentum * velocity Pressure Force = Hydrostatic Pressure, P Friction Force = Force due to Bed Resistance Gravity Force = Contribution in x direction Momentum Equation (Conservation of Momentum) 𝑄 + 𝜕𝑄 𝜕𝑥 ∙ 𝑑𝑥 ∆𝑀 ∆𝑡 = − ∆ 𝑀 ∙ 𝑉 ∆𝑥 − ∆𝑃 ∆𝑥 + 𝐹 𝑔 ∆𝑥 − 𝐹𝑓𝑟𝑖𝑐 ∆𝑥 𝝏𝑸 + 𝝏( 𝑸𝟐 𝑨 ) + 𝒈𝑨 𝝏𝒉 = 𝒈𝑨(𝑺𝟎- 𝑺𝒇) Momentu m Flux Pressur e Force Gravity Force Frictio n Force
- 23. • friction between riverbed and water flow • depends on bed type and slope -> less friction for smooth concrete -> typical friction for normal gravel -> high friction for rough stones/rocks and vegetation • part of Saint Venant equation head loss (potential energy) due to friction along a channel to the average velocity of the fluid flow Resistance 𝑆𝑓 = 𝑚2 (𝐷𝐻/4)4/3 𝑉 𝑉 to is the average boundary shear stress and DH is the hydraulic diameter 𝑆𝑓 = 4𝜏0 𝜌𝑔𝐷𝐻
- 24. • In natural channels, m depends on the channel type (main or flood/overbank channel), regularity and vegetation type Manning’s Values: Natural Channels
- 25. Streams on Plain Manning, m Strickler, Ks =1/m 1 Clean, straight, full stage, no rifts or deep pools 0.025–0.033 30-40 2 Same as above, but more stones and weeds 0.030–0.040 25-33 3 Clean, winding, some pools and shoals 0.033–0.045 22-30 4 Same as above, but some weeds and stones 0.035–0.050 20-29 5 Same as above, lower stages, more ineffective slopes and sections 0.040–0.055 18-25 6 Same as 4, but more stone 0.045–0.060 17-22 7 Sluggish reaches, weedy, deep pools 0.050–0.080 12-22 8 Very weedy reaches, deep pools, or floodways with heavy stand of timber and underbrush 0.075–0.150 07-13 Manning values – examples, minor stream
- 26. • Hydraulic engineering is the application of the principles of fluid mechanics to problems dealing with the collection, storage, control, transport, regulation, measurement, and use of water. • In Australia, The National Committee on Water Engineering (NCWE) is the peak representative body for Engineers Australia members with an interest in surface water hydrology, hydraulics, water quality, water sensitive urban design and water resources. Hydraulic engineering
- 27. • Hydraulic structures are submerged, partially submerged or floated in water. • By the features of their actions on the stream flow, main hydraulic structures are distinguished as water retaining structures, water conveying structures, and special-purpose structures. Types of Hydraulic Structures
- 28. Dams are typical water retaining structures that affect closure of the stream and create heading-up afflux. • Concrete dams – gravity, flood control, power generation, and water management, e.g. Hume Dam, in the Riverina region of New South Wales, Australia • Embankment dams - The Wivenhoe Dam is a rock and earth-fill embankment dam with a concrete spillway across the Brisbane River in South East Queensland, Australia. Water retaining structures Aerial view of Hume Dam and spillway, 2012 https://en.wikipedia.org/wiki/Hume_Dam en.wikipedia.org/wiki/Wivenhoe_Dam
- 29. The Three Gorges Dam is a hydroelectric gravity dam that spans the Yangtze River, in Yichang, Hubei province, central China, downstream of the Three Gorges. The Three Gorges Dam has been the world's largest power station in terms of installed capacity (22,500 MW) since 2012. Hydroelectric Power https://en.wikipedia.org/wiki/Three_Gorges_Dam The theory is to build a dam on a large river that has a large drop in elevation. The dam stores lots of water behind it in the reservoir. Near the bottom of the dam wall there is the water intake. Gravity causes it to fall through the penstock inside the dam. At the end of the penstock there is a turbine propellor, which is turned by the moving water. The shaft from the turbine goes up into the generator, which produces the power. https://www.usgs.gov/special-topic/water-science-school/science/hydroelectric-power-how-it-works?qt-
- 30. • Water conveying structures are artificial channels cut in the ground and made of either ground materials such as soil and rock (e.g., canals and tunnels) or artificial materials such as concrete and metal (e.g., aqueducts, flumes, siphons, pipelines). Water conveying structures Giant twin pipelines transfer water from Warragamba Dam to Prospect water filtration plant which supplies 80% of Sydney's water www.waternsw.com.au/water- quality/education/learn/water-supply-system South–North Water Transfer Project Central route starting point taocha in Xichuan County, Nanyang, Henan, China en.wikipedia.org/wiki/South%E2%80%93North_Water_Transfer_Project 2 2 2 3 3 1 1 2 2 1 2 3 p v p v p v z z z + + = + + = + +
- 31. Divided roads may have an open drain in the median. Drainage system The flow velocity depends on the discharge rate, size and shape of the channel, slope of the channel, and lining (roughness) of the channel.
- 32. Culverts-Cross drainage structures • Used to carry flow through obstructions • Road embankments • Railway embankments • Various Configurations/ cross sections • Single • Multi-Cell • Link slab • Various materials • Concrete • the most common • Corrugated steel • Aluminum
- 33. Coastal protection – breakwaters, seawalls, Special-purpose hydraulic structures http://www.news.com.au/technology/enviro nment/japans-radical-bid-to-fend-off- tsunamis-with-giant-400km-sea-wall/news- story/79f7fb40e54654953d7ab61cfeed3be5 https://beachesgoldcoast.com.au/projects/ Breakwaters - structures constructed near the coasts as part of coastal management or to protect an anchorage from the effects of both weather and longshore drift.
- 34. Resources and aquaculture – offshore platform, fish farms Special-purpose hydraulic structures https://maintenanceandcure.com/maritime-blog/the- difference-between-vessel-and-platform-rigs/ https://www.maritime-executive.com/article/norway-targets- offshore-fish-farm-innovation