USN 10cv4s

(06 Marks)

(08 Marks)

, (06 Marks)

expression for the depth of hydraulic jump in(08 Nlarks)

Fourth Semester B.E. Degree Examination, Dec.2013 lJan.20l{Hydraulics & Hydraulic Machines

Max. Marks:100Time: 3 hrs.

2a.

b.

Note: Answer FIVEfull questions, selectingat lesst TWO questions from each port,

PART _ A

a.

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State the Buckingham theorem and mention the advantages of dimensional uralysisloo Marks)

Capillary rise h depends on density p, acceleration due to gr,avity g, surface tension oand radius of the tube r. Show by using the Buckingham n-theorem that

1-, '( o)(08 Marks)=01 --. Ir \Pgr')

c. In the model of a spillway, the discharge and velocity of the flow over the model were2rilsec and 1.5 m/sec, respictively. Calculate V and Q over the prototype spillway if thescale is 1/36. ' (06 Marks)

Derive an expression for the discharge through an open channel using Chezy's formula.(06 Marks)

A flow of water flows at 150 litres per second in a rectangular channel of width 70 cm anddepth of flow 40 cm. Uniform flow occurs at a certain bed slope with Chezy's C equal to 60.

c. A canal is to have a trapezoidal section with one side vertical and the other sloping at 45'. Ithas to carry 30 m'/sec of water with a mean velocity of 1 m/sec. Compute the dimensions of

Find the bed slope of the channel.

the section which will require the minimum lining.

3 a. What is specific energy curve? Draw specific energy curve and then derive expressions forcritical depth and critical velocity. (06 Marks)

b. Show that the relation between alternate depth )1 and yz in a rectangular channel can be

expressed by

,,, _ 2yly)J ' (y, *yr)

c. Explain the term hydraulic jump. Derive anterms of the upstream Froude number.

4 a. Find an expression lor the efficiency of a series of moving curved vanes when a jet of waterstrikes the vanes at one of its tips. Prove that maximum efficiency is when u : v and thevalue of maximum efficiency is 50%, (10 Marks)

b. A jet of water coming out of a nozzle of 10 cm diameter with a velocity of 10 m/sec strikesthe flat plate. Find out the force exerted on the plate, work done, power developed andefficiency when (i) plate is stationary (ii) plate is moving with a velocity of 10 m/sectowards the jet (iii) plate is moving with a velocity of 10 misec the jet

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(10 Marks)

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5a.

b.

la.

b.

8a.

b.

10cv45

PART _ B

Prove that the work done per second on a series of moving curved radial vane is

pav, [v*,u, * v*, u, ] (10 Marks)

A jet of water having a velocity of 35 m/sec impinges on a series of vanes moving with a

velocity of 20 m/sec. The jet makes an angle of 30' to the direction of motion of vahes when

entering and leaves at an angle of 120o. Draw the triangles of velocities at inlet and outletand find:(i) The angles of vanes tips so that water enters and leaves without shock.

(ii) The work done per unit weight of water entering the vanes.(iii) The efficiency.

a. Obtain an expr€ssion for the work done per second by water onthe runner of a Pelton wheel.

b. Design a Pelton wheelwith the lollowing data:

Shaft power :735.75 kW ; H : 200 m ;

Cv: 0.98 , $ :0.45. r'

Determine D, d and number ofjets

What are the uses of a draft tube? Describe with neat sketches different types of draft tubes.,: (08 Marks)

A Kaplan turbine working under a head of 20. m develops 11772 kW shaft power. The outletdiameter of the runner is 3.5 m and hub diameter 1.75 m. The guide blade angle at theextreme edge of the runner is 35o. The hydraulic,and overall efficiencies of the turbines are

88% and 84olo respective$irlf the velocity of whirl is zgro at outlet, determine:(D Runner vane angles-at inlet and outlet at the extrerhe edge of the runner and(ii) Speed or,n.,,,,u.O*". (12 Marks)

Define a centfifugal pump. Explain the working of a singld-sthge centrifugal pump withsketches. : (08 Marks)A centrifual pump delivers water against a net head of 14.5 meties and a design speed of1000 qpm. The vanes are curved back to an angle of 30o with the periphery. The impellerdiameter is 300 mm and outlet width 50 mm. Determine the discharge of the pump, if

(10 Marks)

(10 Marks)

N.= 800 rym ; 116 : 0.86 , ? =,0,

manometric efficiency is 95oh.

(10 Marks)

(12 Marks)

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