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USN I I I I I I I I I IJFourth Semester B.E . Degree Examination
, June-July 2009
Fluid MechanicsTime: 3 hrs. Max. Marks: I00
No te: 4m;wer any FI VE ull questions dw osiiiJ: at /('ast
twoq11estion .\ from each unit.
PART - Aa. Give reasons
1) V1scos1ty of liquids v a r i c . ~ with temperature11) TbJ.n
objects Goat on fu:e surface ofstatic liquid.aii) Mct.u;cn!nc
height c r m i n ~ stability of floating body.iv) lose of water in
a C'alilary tube.v) Mercury IS used as Marometric liquid. (05 :\ta
rkJb. Define following tei11Js wn h their umts.i) Specific Weight
11) ~ m c m a l l e VISCOSity iii) SurfiiCt: r e n ~ i o n IV)
Specific gravity ; v) Capillarity (OS M ork!J)
c. The space between twu squarc flat parallel plates is filled
with 011. Each sidc of he plates 1s800 mm. Th1ckness of he oillilm
is 20 mm. The upper plate moves at a unifom1 vdocll)' of3.2 mls\.'C
when a ti)rcc of 50 1\ applied to upper plate. Determinei) Shear
stressii) Dynamic visc1sity of oi l in poise
ii1) Power absorbed 111 movi og the plate1v) Kmematlc viscos1ty
ofo1l if spet.1fic gravity ofoil is 0.90. (JO \ larb)
2 a. State and provc Hydrostatic law t ~ S Morklb. Wuh neat
sketch, cxplam workint: of l iftcreutial u Tube Manometer and
derive relation formc;1sunng p r ~ s u r c d1lfercncc betwet.'l1
two p1pcs. (OS Mark!J)c. A wooden block of ~ i z e 6m ' l Sm x 3m
height floats m freshwater. Fmd the depth ofmmersion and detcnmne
the metacentric height Spcctfy gravlly of wood is 0. 70. Find
thevolume of concrctc block placed on the woudcn block, so as to
completely subm::rgc the
wooden block m water Take specific gravity of concrete as J.O. (
I t \hr l i . )3 a. Explam expcnmental procedure to determine the
metacentnc height of a floating vessel
(fl4l\larl.
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5 a. State and prove Bernoulli's equation for a 11uid flow.
Mention assumptions made mderivation. (10 Marks)b. Water is flowing
through a taper pipe of length 150m, having diameter 500 mm at the
upperend and 250mm at the lower end. Rate of now is 70 liters per
sec. The pipeline has a slopeof I in 30. Find the pressure at the
lower end i f he pressure at higher level is 2.5 bar.(10Marks)
6 a. Explain with neat sketch, working of pilot-static tube. (OS
Marks)b. Differentiate between Orificemeter and venturimeter with
neat sketches. (OS Marks)c. A horizontal venturimcter with 50cm
diameter at inlet and 20cm throat diameter is used formeasuring
rate of water flow, if the pressure at inlet is 1.8 Bar and vaccum
pressure at thethroat is 30crn of mercury, find the rate of flow.
Assume l 0% differential pressure head islost between the inlet and
throat section. Assume coefficient ofdischarge is 0.96.
(10Marks)
7 n. Derive Hagen-poiseulle's equation for viscous now through a
circular pipe. (10 : \ l a r k . ~ ) b. Rate of water flow through
a horizontal pipe is 0.030 m3/sec. Length of pipe is 1000
meters.
Diameter of pipe for first half of length is 200mm and suddenly
changes to 400mrn forremairung length. Find the elevation
difference between the two reservoirs connected by thehorizontal
pipeline. Take O . O I for material of pipeline. (10 Marks)8 a.
Explain terms :i) Lift
ii) Dragiii) Displacement thicknessiv) Momentum thickness (08
Marks)b. Explain Mach angle and Mach cone. (04 MarL.)c. A
projectile travels in air of pressnrc 15 N/cm2 at 10C, at a speed
of 1500 kmlhr. Find theMach number and Mach an!!le. Assume 1'=1.4
and R=-287 Jlk2K 108 Marks\
