Assignment(15markah)Silahantarassignmentinisebelumataupada21hbDisember2017,dibilikkuliahBK2,E07,dari pukul 10 pagi hingga pukul 11 pagi sahaja. Kegagalan berbuat demikian bolehmenyebabkan tiadamarkah yangakandiberikanuntukassignment ini. Kepada yang inginmenghantarawal,bolehmenghantarassignmentinidibilikC23-434.Silaletakkandikotakkuningdihadapanbilikberkenaan.Silakepilkanlampirankompilasijawapaninisebagaimukahadapanlaporanassignmentini.

SILA JAWAB SEMUA SOALAN, TETAPI BEBERAPA SOALANYANGDINYATAKANDIBAWAH,SILATULISJAWAPANANDADIDALAMKOTAKJAWAPANYANGDISEDIAKAN.NAMA:_______________________________________________

Soalan JawapanQ1 a b

Q2 b Q3 b Q4 a b

Q5 b Q6 b Q7 b Q8 b Q9 b Q10 b c

Q11 b Q12 b c

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Ql. Figure Ql slrows a long solid cylinder of radius 0.8 m hinged at point A is uscd as anautomatic gate for a water reservoir. The weight of the cylinder is determined in such away that the gate starts to open as the water level reaches 5 m.

Figure Ql

(a)(b)(c)

What is hydrostatic force?Prove that the location of centre of pressure is different than the centre of gravity.

Determine the weight of the cylinder per unit length of the cylinder.

Be careful to state any assumptions you make

(10 marks)

Q1

Q2. (a)

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Describe the application of mornentum eguation in the operation of fluidmachineries. Give any suitable example of application.

(2 marks)

A water jet strikes on a curved surface of a rigid block as shown in Figure e2.The diameter of the water jet is 50 mm and its velocity is 0.65 m/s. If the frictionon the curved surface is negligible, calculate the magnitude and the direction ofthe reaction force by the block in relation to the water jet. Given the angle, 0 is50"and the jet flows is assumed in a horizontal plane. If the jet flows in a verticalplane, write the equation for reaction force by the block to water jet.

( 8 marks)

(b)

v

Y' \ l

" \ l

\ \ l

\ \\ \\ \ \\ \ \\1t\ \

LI outgoing flow

Figure Q2

Q2

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Q3. Explain with the help of sketches:

Hydraulic grade line, and

Energy grade line.

(2 marks)

A vented tanker is to be filled with fuel oil with density 900 kg/r'and dynamicviscosity 0.05 kg/m.s from an underground reservoir using a 20 m long, 50 mmdiameter plastic hose with a slightly rounded entrance, two flanged 90o smoothbends and a fully open ball valve. The elevation difference between the oil levelin the reservoir and the top of the tanker where the hose is discharged is 4 m. Thecapacity of the tanker is 20 m3 and the filling time is 30 minutes. lf the overallefficiency of the pump is 80 percent, determine the required power input to thepump.

Ret-er Appendix A and B

(8 marks)

(a)

(i ).

(i i).

v(b).

rlv

Q3

Q4. (a)

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Tlrc torque, Idelivered by a water turbine depends upon discharge Q,heuld l/, density p,

angular velocity rrr, gravity g and efficiency l. By using the Buckingham z theorem,determine the form of the equation for torque.

(6 marks)

A spherical balloon to be used in air at 20oC is tested by towing a l/3 modelsubmerged in a water tank. If the model is I m in diameter and the drag force ismeasured as 200 N at a model speed of 1.2 m/q what would be the expectedprototype drag if the water temperature was l5qC? Model and prototype areassumed dynamically similar.

(4 marks)

(b)

\t

lv

Q4

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QUESTTON 1

Ia)

(b)

State three (3) assumptions necessary to use the continuity and Bernoulli equationswhen analyzing a particular flow.

(2 marks)

oil (sG = 0.88) flows in an inclined pipe at a rate of 0.14 mr/s as shown in Figure Ql.If the differential reading in mercury manometer is 0.9 m, calculate the power thatthe pump supplies to the oil if head losses are negligible.

(8 marks)

Flgure Ql

v

.l

v

-I0.9 m

t

Q5

v

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OI]ESTION 2

(a) Derive an expression for the force exerted by a jet of water on a fixed verticalplate in the direction of the jet.

(2 marks)

(b) The piping system shown in Figure Q2 has negligible frictional losses. Eachpipe has an inside diameter of 12 cm. The flow entering through pipe 1 witha flowrate Qr = 0.05 m3/s leaves through 6 cm diameter free iets 2 and 3, aslabeled. The piping carries water having density p = 999 kg/mr. Determinethe velocities in each pipe and the horizontal forces of the water on thepiping system.

(8 marks)

2nr

2nr

cm

Figure Q2

Q6

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quEsTroN 3

(a) For a very rough pipe wall the friction factor is constant at high Reynolds numbers.For a length Lr the pressure drop over the length is Ap1. If the mass flow rate of thefluid in the pipe is then doubled what is the relation of the new pressure drop Ap2tothe original pressure drop Ap1?

(2 marks)

A square tank with an area of 900 mm x 900 mm is drained via a 60 mm diameterpipe O m in length as shown in Figure Q3. The pipe has two bends along its lengthwith head loss coefficients K= 0.6 each, and the entry of the pipe is rounded with K=0.5. The outlet of the pipe is 230 mm below the level of the base of the tank What isthe depth of water in the tank when the rate of flow through the pipe is 7 liters persecond? Starting from this condition, how much water will drain from the tank inthe next 3 minutes? Assume coefficient of friction,/= 0.032.

(8 marks)

0.6

(b)

v

a

NscFc\l

Figure Q3

t'l {!_, llr j

Q7

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QUESTTON 4

(b) Sate Buckingham's n Theorems.(2 marks)

(c) fflr:Iffi:J:.,: # T:ff'.'ffii::il:;,il:;:#::H:;::D and length I due to laminar flow depends on the veloctty 7, viscoslty p density p,and pipe roughness, a Use Buckingham's n Theorems to calculate the velocity of air

_ in a 2 cm diameter plpe whtch will $ve ldnematically simllar condltlons.v

If the preszure drop over a certain length of pipe bearing water is 1 lN/mz, what isthe equlvalent pressure drop in the pipe bearing air?

For water kinematic viscosity was 1.31 x 10-6 6z/s and density 1000 kg/ms. Forair those quantities were 15.1 x 10-6 6z/s and 1.19 kg/mr.

(8 marks)

'l

-

ych , , . , . , ,+. ' ' * ; h

(a)

(b)

Q8

(a) A glass manometer with oil as the working fluid is connected to an air duct as shown inFigure al(a!. Wll the oil levels in the manometer be as in (o/ or lb)? Explain. Whatwould your response be if the flow direction reversed?

-=-=

Figure Q1(al

[2 marksl

A pipe Indined at 35'to the horizontal as shorrn in Figure Ctl(bl conrrcrBc over a lengthI frorn a diameter \ of 2fi mrn at the lower end to a diameter 02 of 15O mm at theupper end. Oil f,onr through the pipe at a mean vetoc'ity V1 of 3 m/s at the tower end.t tsirg dre Senrqdli equilion, find(i) the pressure difference across the 2.5 m length ignoring any loss of energy, and(iil the reading of differential manometer, ft, onnected across this lengh.

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SGsg:13.6 '-

Figure Ql(bl

4-150nnt

v

(bl

Y2

\vDl=250 mm

Vt:3 m/s

[8 marksl

Q9

(bl

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(a) Based on the Reynolds Transport Theorem given below, prove that the linearmomentum equation could be reduced to F = th(Av), state your assumption

]ttr,) = * [*uo av + [*ur, 'ft dA

[2 marksl

Water flovus ttrorgh the duct in Figure Q2, which is 50 cm height and 1 m wide (into thepaperl. Gat€ 8C completely closes the duct when P = 900. Assuming onedimensionalflor, for what argl€ p ruould the plate be stationary?

[5 marksl

F-3l | {

8y maintaining the gate angle in (bf, wtrat rvould be the force on the plate if the plate ismwirg away frorn the gate at2mls?

l3marksl

Y

(cl

v

Fleure (U

Q10

(a)

(b)

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QUESnON 3

Explain one major difference between major losses and minor losses in flow throughpipes.

[2 marksJ

A water filtration systems as shown in Figure Q3 typically use a filtration process wherebythe water passes through a filter made of membrane (K = 12.0) that traps dirt. Supposethat the water (p = 997 kglm3i F = 8.9 x 10{ N.s/m2) is constantly pumped at the rate of0.002 m3A through the piping system that comprised of a 1 m long with 50 mm diameterpipe A8, a total of 5 m long with 25 mm diam€ter pipes cD, two 90'regular elbows, anopen globe valve, and sharp-edged entrance and exit, determine the power [hp] valuethat must be added to water by the pump. All pipes are made of commercial steel (e =

O.(X6 mm) and allcomponents are flanged.

[8 marksl

Filtcr

Figure Q3

v

v

Q11

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(a) To achieve complete similarity bettveen a model and a prototype for any fluid flowanalysis, all three similarities (geometric, dynamic and kinematic) should be maintained.Choose one of the similarities and explain how similarity between a model and aprototype could be achieved.

[2 marksl

(bl The porrver omput (4 of a marine current turbine is assumed to be a function of seawaterqJrrent t'elocity U, blade length [, angular velocity ar, fluid density p and kinematicviscosity v. Using dimensional analysis, shorthat

P ^ -(af lUl \W=JIU,;)

[5 marksl

(cl Marine qtrrerrt turbine is proposed to be buih near Layang-tayang lsland, Sabah. fhecurre{rt velodry is determined to be U = 1.0 m/s and the argular rrelocity of the turbine isexpected to rotate at 16 rpm. A 1:10 scale laboratory model is to be tested in watertunnel of the same density with angular velodty 80 rpm. Using the information in (bl andif the power output in the model tests is determined to be 150 W, calculate:i. Current nelocity in the model tests.ii. Power output would be ocpected In the prototype.

[3 marksl

J

Q12