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Technical English - I 14th week

Hydraulics

Fluid Mechanics deals with all kinds of Fluid. It deals with compressible, incompressible, highly viscous and low viscous fluid, but Hydraulics deals with only water and water is an incompressible fluid.

fluid mechanics / hydraulics / theoretical / empirical / fluid / liquid / gas / compressible

Differences between Fluid Mechanics and Hydraulics

Fluid Mechanics Hydraulics

1. Theoretical 1. Empirical

2. Refers to both liquids and gasses 2. Refers to liquids (often refers to water)

3. Compressible and incompressible flows 3. Incompressible flows

Early civilizations developed many hydraulic systems and built many canals and dams for irrigating crops, draining swamps, and water supply. The Egyptians and Babylonians constructed canals not only for irrigation but also for defensive purposes. The early people appear to have been more interested in the practical and constructional aspects of hydraulics than in theorizing. No attempts were made at that time to understand the laws of fluid motion. The first notable attempts to rationalize the nature of pressure and flow patterns were undertaken by Greeks. For the first time, they enunciated the laws of hydrostatics and buoyancy, and they developed the first hydraulic equipment such as water clock and pump (piston, screw).

civilization / canal / dam / irrigation / draining / swamp / enunciate / equipment

Today, Turkey has an outstanding cultural heritage. There are noteworthy remains of several waterworks from the Hittite, Urartu, Hellenistic, Roman, Byzantine, Seljukian and Ottoman periods in Turkey. Investigation of historical water works in Anatolia is important both understanding the development of hydraulic engineering, and also protecting all those outstanding cultural monuments of not only the Turkish-Islamic world, but of the entire universal civilization. Here are the examples:

cultural heritage / remains / waterworks / monument / universal / civilization

Image source: The pictures in the slides (#4 thru #13) are taken from the following publication; a) Ozis, U. (1996) Historical water schemes in Turkey. "Water Resources Development" 12(3) 365-401. b) Ozis, U. (1994) Ancient water works in Turkey with regard to the history of hydraulics engineering. Ankara, State Hydraulic Works, Publication for the 40th anniversary of DSI’s foundation, 203 p.

Karakuyu dam, irrigation purpose

2nd Millennium BC

U shape, total length 400 m, h=8 m

Boğazkale (Hattuşa)

Spring water

collection chamber

2nd Millennium BC,

h=2.6 m

Water for drinking and

irrigation

Şamram

canal

8th Cnt BC

L=56 km Materials & Techniques

Clay pipes

Stone pipes

Rock-cut canals

Masonry canals

Lead / Copper pipes

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Aqueduct + Inverted Siphon Aspendos, L=1.4 km, 2nd Century AD

“Homa” Aqueduct, Side, L=340 m 2nd Century AD

2atm

2-3atm

“Yedigöz” aqueduct h=20m

16th century AD

Taşlımüsellim water supply system 16th century AD

Spring water collection chamber

Ancient Edirne Water Conveyance System

“Yerebatan“(Basilica) Covered cistern in Istanbul 6th Century AD, 140 x 70 m

(above right)

City reservoir, Hierapolis 12 x 18 x 2.5 m

Nympheum (Memorial Fountain), Perge

Water for public use

Water distribution in Ephesus

Sewerage networks in Prienne

City reservoir, Hierapolis

12 x 18 x 2.5 m Water supply and sanitary

Pergamon twin tunnels on Selinus River, 200 AD, 720 (2x360) m3/s discharge capacity width 9m, height 7.5m, length 196m & 183m

“Çevlik“ (Seleuceia Pieria) storm overflow protection tunnel and channel

1st Century AD, 6-7 m diameter/ side lengths

Flood protection works

Today, Turkey’s success in the development of waterworks in the republican period is not a coincidence. This 4000 year long tradition of hydraulic technology and engineering gives Turkey a new soul in order to achieve its own objective, which is constructing large-scale water works to irrigate 8.5 billion ha of land and to generate 150 billion KWh/year via over 600 dams and 500 power plants.

Çubuk Dam is the first concrete gravity dam constructed after the foundation of Turkish Republic.

success / waterworks / irrigation / energy production / large-scale / objective / dam

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Ataturk dam, 170 m high rock-fill, 85 million m3 embankment,

2400 MW installed capacity

Urfa twin tunnels, 7.6 m & 26.4 km

The longest irrigation tunnel in the world

Discharge canal of the twin tunnels

Q=330 m3/s; 12 m, h=7m

Image source: The pictures in the slides (#4 thru #13) are taken from the following publication; a) Ozis, U. (1996) Historical water schemes in Turkey. "Water Resources Development" 12(3) 365-401. b) Ozis, U. (1994) Ancient water works in Turkey with regard to the history of hydraulics engineering. Ankara, State Hydraulic Works, Publication for the 40th anniversary of DSI’s foundation, 203 p.

Pipe Flow and Pipe Networks

Free surface flow (Open Channel Flow)

Hydraulic Machines

(Pumps & Turbines)

Dimensional Analysis and Hydraulic Similitude

pipe network / open channel / hydraulic machines / pump / turbine / similitude

conduit / pipe flow / pressurized flow / water supply / pressure drop / head losses

(From the water supply system of Izmir)

Majority of closed conduits have circular cross sections, for this reason the name is “pipe flow”. Pipe flow, a branch of hydraulics, is a type of liquid flow within a closed conduit. In closed conduit flow, the fluid is under pressure. Hence, it is also referred to as “pressurized flow”. In the design and analysis of piping systems, engineers encounter three types of pipe flow problems: Determination of the pressure drop when the

pipe length and diameter are given for a specified flow rate

Determination of the flow rate when the pipe length and diameter are given for a specified pressure drop

Determination of the pipe sizes when the pipe length and flow rate are given for a specified pressure drop

Thus, the determination of “head losses” (the pressure drop at system nodes) is an important engineering factor in the design of pipe networks.

Major Losses: due to friction, significant head loss is associated with the straight portions of pipe flows. This loss can be calculated using the Moody chart and Darcy-Weisbach equation.

Lg2

V

Dh

2

major,L

minorL,major,LLf hh)h(or h

g2

VKh

2

minor,L

Minor Losses: Additional components (valves, bends, tees, contractions, etc) in pipe flows also contribute to the total head loss of the system. Their contributions are generally termed minor losses.

head loss / major & minor losses / Moody chart / valves / bends / tees / contractions

where: λ = Friction Factor L = Pipe Length D = Pipe Diameter V = Flow Velocity g = Gravitational Constant

In the figure above, the abscissa is Reynolds number, Re, and the ordinate is the resistance coefficient f (or λ). Each solid curve is for a constant relative roughness, ks/D, and the values of ks/D are given on the right at the end of each curve.

abscissa / ordinate / resistance coefficient / relative roughness / curve

(From Department of Civil Engineering of Kwame Nkrumah University of Science & Technology. Preliminary Reader In. CE 356 Hydraulic Engineering; S. N. Odai; February 2007 )

minor losses / loss coefficient / sharp edges / slightly rounded / well rounded

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Series pipes

Parallel pipes

series pipes / parallel pipes / discharge / branch / liquid surface level

(From https://www.slideshare.net/louyalhamy/ce-352-chapter4a?next_slideshow=1)

Procedure: a) Divide the network into a number of closed circuits so that each pipe is included in at least one circuit, b) Assume a reasonable distribution of flow in various pipes and compute the head loss in each pipe, c) Compute the algebraic sum of the head losses in each circuit by taking a suitable sign convention, d) Repeat the calculation unless the assumed distribution of flow happens to be correct.

pipe network / loop / branch / ingenious / successive / closed circuit / sign convention

(From Preliminary Reader In. CE 356 Hydraulic Engineering; S. N. Odai; February 2007 )

(From http://mimoza.marmara.edu.tr/~neslihan.semerci/ENVE204/L3.pdf)

Energy level at the system nodes, such as point J, by neglecting minor loses:

EJ = EA - hf1 or EA = EJ + hf1 EB = EJ + hf2 EC = EJ + hf3

hf1: Major head loss between reservoir A and point J (major losses >> minor losses)

EA = hf1 + hf3 + EC EB = hf2 + hf3 + EC

branch piping / energy level / energy grade line (EGL) / system nodes / neglecting

The level in the piezometer is the pressure head and its value is given by p/.

Energy Grade Line (EGL): the sum of the pressure head, the velocity head, and the elevation head.

Hydraulic Grade Line (HGL): the locus of piezometric heads. The difference between energy and hydraulic grade lines is equal to velocity head.

hf the head loss due to friction.

energy & hydraulic grade line / velocity head / pressure head / piezometer / locus

Various sections of open channel

open channel / free surface flow cross sectional area / hydraulic radius / wetted perimeter / free board / discharge rate

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P:Wetted perimeter

A: Cross sectional area of flow

V: Velocity A: Cross sectional area n: Manning roughness coefficient R: Hydraulic radius (R=A/P) So: Channel bottom slope Q: Discharge rate (water flow rate)

Freeboard

water flow rate / flow velocity / channel slope / channel roughness / water flow depth

The Manning equation is useful for a variety of open channel flow calculations involving parameters such as water flow rate, flow velocity, channel slope, channel roughness, water flow depth, and channel size and shape parameters.

best hydraulic cross section / efficient / lining material / cost of construction

(Department of Civil Engineering of Kwame Nkrumah University of Science & Technology. Preliminary Reader In. CE 356 Hydraulic Engineering; S. N. Odai; February 2007 )

Governing equations:

Note that at the throat the water depth H2 is less than H1 since the velocity v2 is greater than v1

H2<H1 since v2>v1

rapidly / gradually / construction / constriction / throat / water surface / datum /

(From https://www.slideshare.net/Umeshpatel68/hydraulic-jump-63224822)

reservoir / hydraulic jump / depth / critical depth line / supercritical & subcritical flow

specific energy / potential energy / energy curve / supercritical & subcritical flow

(From https://www.researchgate.net/ publication/305842743_ Evaluation_of_Field_Feasibility_and_Efficiency_of_Hydraulic_ Ram_Pump)

Fom http://www.energyland. emsd.gov.hk/en/energy/ renewable/hydro.html

Pumps and turbines are energy conversion devices: pumps turn electrical or mechanical energy into fluid energy; turbines turn fluid energy into electrical or mechanical energy.

pump / turbine / device / conversion / fluid energy / electrical & mechanical energy

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kinetic / positive displacement / centrifugal / reciprocating / rotary

From https://www.theprocesspiping.com/introduction-to-pumps/)

https://www.scribd.com/document/252802104/t4

static lift / head losses / suction head / pump head / efficiency / pump power

Pump manufacturers provide Head versus Flow curve for various pump models. The design engineer selects a suitable one from them based on the context.

manufacturer / total head / flow rate / discharge rate / efficiency / pump curve

Series or parallel pumps?

pumps in series / pumps in parallel

https://www.scribd.com/document/252802104/t4

hydropower / turbine / generator / stator / rotor / shaft

Karakaya arched gravity dam and power plant with 1,800 MW capacity

What is the type of pump shown below?