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Totat No. of

Time : Three,V.B. :- (i)

(ii)

(iii)(iu)\ U )

(ui)

l .

Questions-121 lTotal.' No. of Printed pages---4+Z137621-25

S.E. (MECH) EXAMINATION. 2O1OFLI]ID MECIIANICS. (2003couRsE)

Hours Maximum Marks : 100Answer any lhree questions from each Section.Answers to the two sectionsshould be written in separateanswer-books..Neat diagrams i.rust be drawn wherever necessary.Figr:res to the right indicate full marks.Useof logarithmic tables,slide rule; Mollier charts,electronicpocket calculator and steam tables is allowed.Assume suitable data, if necessary.

SECTION I(a) Plot the stress strain relation of the various fluids in onediagramanddiscusshe behaviourofeach luid underan extemalshear foice. t6l(b) A soap bubble, 62.b mrn diameter,.has an internal pressure

in excessof the outside pressureof 20 N/m2. What is tensionin soap film ?\c) Describe various types of flow with examples.

I4lt6l

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Or, (c) The spacebetween wo square lat parallel plates is litled with

oil. Each side of the plate is 720 mn. The thickness of theoil frlm is ' 15 mm' The upper plate' which moves at 3 m./sreouires a force of 120 N to maintain the speed'Determine:(r) The dlnamic viscositY of the oil;(tr) The kinematic viscosity of oil if the specific

oil is 0.95.

passing through these Points.Explain the concept of'Stream tube'

State and explain Pascal's law'Derive an expression for total pressurefor inclined plane submerged in liquidexpression for center of pressure forDefine the following terms :(i) Buoyancy(ii) Centre of buoyancy(lii) Principle of floatation(iu) Archimedes'sPrinciPle.

2

gravity oft6l

t6lwith sketch. t41

t4land center of pressureand hence derive thevertical plane. t81

(b) If O = 3try, frnd .r and , componentsof velocity at (1, 3)and (3, 3). Determine he discharge assingbetweenstreamlines

3. (a)(b)

(c)

(c)

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4. \a)

(r)(ii)

Take137621-23

OrExplain with neat sketchmanometer.

the working of single columnt4t

liquid in motion. l4lfirst principle. t6l

(b)

(c)

A solid cylinder 2 m in diameter and 2 m high is floatingin water with its axis vertical. If the specific gravity of thematerial of cyl inder is 0.65, find its metacentricheight. Statealso whether the equilibrium is stable or unstable. t61

t ' lProve that with usual notations,BM=;. 16l

6. (e)(b)(c)

State different types of heads ofDerive Bernoulli's equation, usingA 300 mrn x 160 mm venturimeter is provided in a verticalpipeline carrying oil of specificgravity 0.9, flow being upward.The difference n elevation.of the throat sectionand entrancesection of the venturirneter is 300 mrn. The differentialU-tube mercury manometer showsa gaugedeflection of 250mm.Calculate:

The discharge of oil, andpressure difference between the entrance section andthroat section.= u,vd ano spectncgravrty ()1mercury as 13.6. [8]

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6. . (a)(o )

CompareWhat iswith allState the

serecf,lng repeatmg varraDres ,Itr

t6lDraw

t8lt4l

t61

\c)

SECTION II(a) Starting from the first principle,derive he expressionorvelocity

at distance 'y' from one fixed plate for laminar flow beo,veentwo parallel. fixed plates. Also find the discharge. t10l(b) What are repeatingvariables / What points are important while

tt. (o). Laminar flow takes.placen a circular ube. At what distancefrom the boundary doesthe local velocity equal the average

t81elocity ?(b) Torque T of a propeller dependson density of liquid p, viscosity

of liquid p, speed of shait N rpm, linear velocity V, diameterof the propeller shaft D.Using Buckinghain r-theorem, show that :

1 = pN2 DP o (ND/V, pND2/u). t81137621-23

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9 . , ( o ) for the power transnrission through thecondition for maximum transmission of

t6l(6) Two reservoirs,having a difference n elevation of 1b m, areconnectedby a 200 mm diameter siphon. The length of thesiphdn is 400 mm and the summit is 3 m above the waterlevel in the upper reservoir.The length of the pipe liom upperreservoir to the summit is 120 m. If the coeffrcientof Iliction

(c)

is 0.005, determine :O Discharge through the siphon, and(il) Pressureat the summit.Neglect minor losses.Explain briefly the following:(it Hydraulic Grade Line (HGL)(iD Energy Grade Line (EGL).

Or10. (a) In a 80 mm diameter pipeline an oii of specific gravity 0.gis flowing at the rate of 6.0128 m3/s. A sudden expansiontakesplace nto a second ipelineof suchdiameter hat maximumpressure r.ise is ,obtained. Find :

ti) Loss of energy in suddenexpansion;(iD Differential gauge length indicated by an oil_mercury

.Derivepipes.power.

Derive Dupit's equation.Dxplain major and minor losses

an expressronFind also the

manometer connectedbetween the two

t8l

t2l

(b)(c) occurred in pipe.

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11. (a)

(b)

clearly between hydrodl.namically smooth and

importance of the following

rought6l

layeroundary

t6lfinite lengthshear dragif the totai

respectively.t6l

12. (o) Explain the significanceof the boundary ayer concept n tluidmechanics. t61(b) Explain development f fully developedurbulent flow in circularpipes with bketches. t61

(c) Define 'angle of attack'for an aerofoil. Expiain its significance. clearly. 161

lc.,

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