LAB COPYFLUID MECHANICS - 01

INSTRUCTER: ENGR SAEEDPREPARED BY: KAMRAN KHAN

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PRACTICLE NO. 01

TITLE

DEMONSTRATION OF VARIOS PARTS OF HYDRAULICBENCH

HYDRAULIC BENCHHydraulic bench is a very useful apparatus in hydraulics and fluid mechanics. It is involved inmajority of experiments to be conducted e.g. to find the value of the co-efficient of velocity 'Cv',coefficient of discharge 'Cd', to study the characteristics of flow over notches, to find metacentricheight, to find head losses through pipes, to verify Bernoulli's theorem etc.

PARTS

Its parts are given below.Centrifugal pumpIt draws water from sump tank and supplies it for performing experiments.Sump tankIt stores water for Hydraulic bench. It is located in the bottom portion of Hydraulic bench. Waterfrom here is transported to other parts by using a pump. It has a capacity of 160 lits.Vertical pipeIt supplies water to the upper part of hydraulic bench from sump tank through a pump.Control valveIt is used to regulate the flow in the pipe i.e. to increase or decrease the inflow of water in thehydraulic bench.Connecter

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With the help of this we can attach accessories with the hydraulic bench. Special purpose terminationsmay be connected to the pump supply by unscrewing connecter, no hand tools are required for doing so.It is located in the channel.ChannelIt is used in number of experiments It provides passage for water for different experiments.Drain valveIt is used for emptying sump tank.Side channelsThey are the upper sides of the channel. They are used to attach accessories on test.Volumetric tankIt stores water coming from channel. This tank is stepped to accommodate low or high flow rates. Ithas a capacity of 46 lits.Stilling baffleIt decreases the turbulence of water coming from channel. It is located in the volumetric tank.Scale & TappingA sight tube and scale is connected to a tapping in the base of the volumetric tank and gives aninstantaneous indication of water level.Dump valveIt is used for emptying volumetric tank. It is located in the bottom of the volumetric tank.ActuatorDump valve is operated by a remote actuator, lifting actuator opens the dump valve, when it is givena turn of 90' it will turn the dump valve in the open position.Over flowIt is an opening in the upper portion of the volumetric tank. It sends the water level above 46 lits tothe sump tank.Measuring cylinderA measuring cylinder is provided for measuring of very small flow rate. The cylinder is stored in thecompartment housing the pump.StarterIt on / off the hydraulicbench.

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LAB COPYFLUID MECHANICS - 01

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PRACTICLE NO. 02TITLE

To calibrate a pressure gauge using a dead weight pressure gauge calibratorAPPARATUS

1) Dead weight pressure gauge calibrator having the following main components,a) Cylinderb) Weightsc) Leveling screwsd) Spirit levele) Cylinder inlet

2) A gauge to be calibrated 3) Hydraulic bench

Concepts:Calibration:To compare the values of an instrument with that of the standard ones is known as calibration of thatinstrument.Pressure gauges:The instruments with the help of which we measure the pressure are called as the pressure gauges.Absolute pressure:The pressure measured with reference to absolute zero is called as absolute pressure.Gauge pressure:The pressure measured with the atmospheric pressure is called as gauge pressure.Vacuum pressure:Negative gauge pressure is known as vacuum pressure.Atmospheric pressure:The pressure exerted by the atmosphere above us is known as the atmospheric pressure.Its standard values are given below.1 atm = 14.7psi = 101300Pa = 0.1Mpa = 76cm of Hg = 760 mm of Hg

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= 1.01 bar = 34' of water

PROCEDURE:

1) I placed the pressure gauge and calibrate assembly on bench top.2) I connected the inlet tube to the gauge manifold.3) A length of tube was connected to the calibrator drain and laid into the channel to

prevent spillage of water on the bench top.4) The calibrator was leveled by the adjusting feel whilst observing the spirit level.5) I removed the piston and accurately determined its mass.6) I closed the control valve of the bench and open both cocks then I operated the pump

starter and also open the control valve and admitted the water to the cylinder.7) After removal of air bubbles from the tube, I closed the cock along with flow control

valve and switched of the pump.8) I noted the gauge readings corresponding to the piston mass of .5 kg.9) Then I added .5 kg mass each time and noted the corresponding gauge readings.10) Then I find out the Absolute gauge error by the following formula.Absolute gauge error = Pressure in cylinder - Gauge reading11) Then I find out the %age gauge error by the following formula. %Age gauge error = Absolute gauge error *100 / Pressure in cylinder12) Then I plotted a graph between %age gauge error and pressure in cylinder.

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Observations and calculations

S.No

PistonmassKg

Pistonarea

m2

Pressurein cylinder

KN/m2

=F/A

GaugereadingsKN/m2

Absolutegaugeerror

KN/m2

%Agegaugeerror

1 0.5 244.8*10-6 2042.48 10 2032.48 99.512 1 244.8*10-6 4084.96 30 4054.96 99.263 1.5 244.8*10-6 6127.45 50 6077.45 99.184 2 244.8*10-6 8169.93 69 8100.93 99.155 2.5 244.8*10-6 10212.41 89 10123.41 99.12

GRAPH

GRAPH B/W %AGE GAUGE ERROR &PRESSURE IN CYLINDER

0

2000

4000

6000

8000

10000

12000

99.1 99.2 99.3 99.4 99.5 99.6

%AGE GAUGE ERROR

PRES

SUR

E IN

CYL

IND

ER

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LAB COPYFLUID MECHANICS - 01

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PRACTICLE NO. 03TITLE:

Experimental study of Laminar, Transitional and TurbulentFlow

APPARATUS:1) Hydraulic bench2) Osborne Reynolds apparatus Osborne Reynolds apparatus includes the following parts:

a) support columnsb) visualization pipesc) outlet control valved) needlee) reservoirf) marble glasses (kanchi) for smoothness of flowg) starterh) overflow pipei) inlet pipej) dye reservoirk) bil mouthl) dye control valve

ConceptsLaminar flow:The type of flow in which the particles move in a straight line in the form of a thinparallel sheets is known as the Laminar flow.Turbulent flow:The type of flow in which the particles move in a zigzag pattern is known as theturbulent flow.Transitional flow:When the flow changes from laminar to turbulent or vice versa a disturbance is created,it is called as the transitional flow.

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Open channel flow:When flow is exposed to the environment whether in pipes or open then itis called as theopen channel flow.Closed channel flow:When flow is not directly exposed to the environment then it is called asthe closed orpipe flow.There are two ways to categorize a flow:a) By visualizationb) By calculationWhen liquid flows there are three forces acting on it:a) Inertial forceb) Gravitational forcec) Viscous forceREYNOLDS NUMBER:It is the ratio of inertial force to the viscousforce.Mathematically it is given asRN= v * D/�If1) RN= 0 to 2000Then flow will be laminar.

2) R N = 2000 to 4000Then flow will be transitional. 3) RN= greater than 4000 Then flow will be turbulent.

PROCEDURE1) I filled the reservoir with dye.2) I positioned the apparatus on the bench and connected the inlet pipe to the bench feet.3) Then I lowered the dye injector until it was just above the bell mouth inlet.4) I opened the bench inlet valve and slowly filled head tank to the overflow level, then closed

the inlet valve.5) Then I opened and closed the flow control valve to admit water to the flow visualization

pipe.6) I opened the inlet valve slightly until water traveled from the outlet pipe.7) I fractionally opened the control valve and adjusted dye control valve until slow flow with

dye indication is achieved.8) At low flow rates the dye was drawn through the center of the pipe.9) I increased the flow rate that produce eddies in the dye until the dye completely dispersed into

the water.10) I visually observed the three types of flow.11) When the dye was looking like a line then I categorized it as Laminar flow.12) When the dye was looking dispersed I categorized it as Turbulent flow.13) When the dye was looking like a line at some instant and dispersed at some times I

categorized it as Transitional flow.

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PRACTICLE NO. 04TITLE:

To determine the metacentric height of a ship modelAPPARATUS:

1) Water bulb2) Metacentric height apparatus3) Scale or measuring tube

CONCEPTS:Metacenter:When a floating body is given a small displacement it will rotate about a point, so the point at whichthe body rotates is called as the Metacenter."OR"The intersection of the lines passing through the original center of buoyancy and center of gravity ofthe body and the vertical line through the new center of buoyancy.Metacentric height:The distance between center of gravity of a floating body and Metacenter is called as Metacentricheight.Why to find Metacentric height?It is necessary for the stability of a floating body, If metacenter is above center ofgravity body will bestable because the restoring couple produced will shift the body to its original position.Center of buoyancy:The point though which the force of buoyancy is supposed to pass is called as the center of buoyancy."OR"The center of area of the immersed portion of a body is called its center of buoyancy.

PROCEDURE:

1) First of all I adjust the movable weight along the vertical rod at a certain position andmeasured the distance of center of gravity by measuring tape.

2) Then I brought the body in the water tube and changed the horizontal moving load distancefirst towards right.

3) The piston tilted and suspended rod gave the angle of head, I noted the angle for respectivedisplacements.

4) I did the same procedure for movable mass by changing its position towards left.5) Then I took the body from water tube and find another center of gravity by changing the

position of vertically moving load.6) I again brought the body in the water tube and find the angle of head by first keeping the

movable load towards right and then towards left.7) I repeated the above procedure for another center of gravity.8) I calculated the metacentric height by the following formula: M H = w * d / W * tanØ Where MH = Metacentric heightw = Horizontally movable mass d = Distance of movable mass at right or left of center W = Mass of assemble position

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Ø = Respective angle of heel

OBSEERVARIONS & CALCULATIONS

Horizontally movable mass = w = 0.31kg Mass of assemble position = W = 1.478kg

Center of gravity = y1 = 8 mm Center of gravity = y2 = 9 mm Center of gravity = y3 = 10 mm

CONSIDERING RIGHT PORTION

S.No

Dist of movablemass at right of

center"d" (mm)

Angle of head"Ø"for

Metacentric heightMH (mm)

for

y 1 y 2 y 3 y 1 y 2 y 3

1 20 2.5 2.75 3.3 96.07 87.33 72.752 40 4.5 5.5 6 106.6 87.13 79.823 60 7.5 9 9.5 95.58 79.45 75.20

CONSIDERING LEFT PORTION

S.No

Dist of movablemass at left of

center"d"(mm)

Angle of head"Ø"for

Metacentric heightMH (mm)

for

y 1 y 2 y 3 y 1 y 2 y 3

1 20 2.5 2.75 3.5 96.07 87.33 68.582 40 4.5 5.5 6 106.6 87.13 79.823 60 7.5 9.75 10 95.58 73.23 71.37

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LAB COPYFLUID MECHANICS - 01

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EXPERIMENT NO: 05

CALIBRATION OF RECTANGULAR NOTCH"OR"

CALIBRATION OF U - NOTCH" OR"

TO DETERMINE COEFFICIENT OF DISCHARGE OF ARECTEANGULAR NOTCH

APPARATUS:1) Hydraulic bench2) Stopwatch3) Rectangularnotch CONCEPTS:NOTCH:A Notch is regarded as an orifice with water level below its upper edge.Notch is made of a metallic plate and its use is to measure the discharge of liquids.These are used for measuring the flow of water from a vessel or tank with no pressure flow.Since the top edge of the notch above the liquid level serves no purpose therefore a notch may haveonly bottom edge and sides.SILL "OR" CREST OF A NOTCH:The bottom edge over which liquid flows is known as Sill or Crest ofthe notch.RECTANGULAR NOTCH:The notch which is Rectangular in shape is called as the rectangular notch.Coefficient of discharge (Cd):It is the ratio between the actual discharge and the theoretical discharge.Mathematically: Cd = Q

actual / Q theoratical

Q theoratical = 2 / 3 *b *√2g * H 3 / 2

Q actual = Cd * 2 / 3 *b *√2g * H 3 / 2

Q actual = k H 3 / 2

Taking log on both hand sides:Log Q = Log k + 3 / 2 Log HNow hereLog k = InterceptK = log - 1(Intercept)

K = 2 / 3 *Cd*b*√2g

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PROCEDURE:The stepwise procedure is given below:1) Fix the plate having rectangular notch in the water passage of Hydraulic bench.2) Turn the hydraulic bench on; water will accumulate in the channel.3) When the water level reaches the Crest or sill of notch stop the inflow and note the reading,

and design it as H1.4) Restart the bench and note the volume and time of water that accumulates in the volumetric

tank of bench, from this find the discharge, and also note the height of water at this point.5) Find H = H2 - H1

This will give you the head over the notch.6) Find the width of the notch.7) Take different readings by changing the discharge head over the notch, using the above

procedure.8) Plot a graph between Log 10H and Log10Q and find K from graph equation.9) Find Cd from the following formula. Cd = 2 / 3 * k / √2g * b

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OBSERVATIONS & CALCULATIONS

b =3 cm

S.No H1cm

H2cm

Hcm

VolumeLiter

TimeSec

QCm3/sec

Log10H Log 10Q

1 8. 6 11. 3 2.7 5 16.5 8 301.5 6 0.431 2.472 8. 6 12. 6 4 5 9.2 6 539.95 0.60 2 2.733 8. 6 13.7 5.1 5 6.8 2 733.1 3 0.707 2.8 64 8. 6 14. 6 6 5 5.01 998.00 3 0.77 8 3

GRAPH:

CALIBRATION CURVE

0

0.5

1

1.5

2

2.5

3

3.5

0 0.2 0.4 0.6 0.8 1

Log10H

log1

0Q

y = 1.492x + 1.825 8GRAPH EQUATION:

0.431,2.47

0.602,2.73

0.707,2.86

0.778, 3

AsY - Intercept = Log 10K = 1.8258

SoK = Log 10-1[ 1.8258 ]

K = 12.6683Also

Cd = 3 * k / 2 * √2g * bCd = 0.143

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