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VTU Civil Engineering (Semester 4)
Hydraulics & Hydraulic Machines
June 2015
Total marks: --
Total time: --
INSTRUCTIONS
(1) Assume appropriate data and state your reasons
(2) Marks are given to the right of every question
(3) Draw neat diagrams wherever necessary

1 (a) Explain the terms: distorted models and undistorted models.
4 M
1 (b) Explain Froude's model law. List its application in fluid flow problems.
6 M

2 (a) What do you understand best hydraulic channel section? Derive the conditions for best hydraulic triangular channel section.
10 M
2 (b) A trapezoidal channel with side sloper of 3 horizontal to 2 vertical has to be designed to convey 10 m3/s at a velocity of 1.5 m/s, so that the amount of concrete lining for the bed and sides is minimum. Find: i) The watted perimeter; ii) Slope of the bed if Manning's n=0.014.
10 M

3 (a) Derive the differential equation for gradually varied flow and list all the assumptions.
10 M
3 (b) A discharge of 18 m3/s flows through a rectangular channel 6m wide at a depth of 1.6m. Find:
ii) Critical depth
iii) State weather the flow is subcritical or supercritical
iv) What is the depth alternate to the given above?
10 M

4 (a) Derive the expressions for force exerted by a jet on an inclined plate in the direction of the jet. i) When the plate is stationary? and ii) When the plate is moving in the direction of jet?
10 M
4 (b) A jet of water of diameter 25mm strikes a 200mm×200mm square plate of uniform thickness with a velocity of 10m/s at the centre of the plate which is suspended vertically by a hinge on its top horizontal edge. The weight of the plate is 98.1 N. The jet strikes normal to the plate. What force must be applied at the lower edge of the plate so that plate is kept vertical? If the plate is allowed to deflect freely, what will be the inclination of the plate with vertical due to the force exerted by the jet of water?
10 M

5 (a) Show that for a free jet of water striking at the centre of a symmetrical curved vane the maximum efficiency is slightly less than 60%.
10 M
5 (b) A jet of water having velocity 45m/s impinges without shock on a series of vane moving at 15 m/s, the direction of motion of vanes being inclined at 20° to that of the jet. The relative velocity at the outlet is 0.9 of that at inlet, and the absolute velocity of the water at the exit is to be normal to the motion of vanes. Find: i) Vane angles at entrance and exit and ii) Hydraulic efficiency.
10 M

6 (a) Classify and explain different types of turbines.
10 M
6 (b) A penstock supplies water from reservoir to the Pelton Wheel with a gross head of 500m. One third of the gross head lost in friction in the penstock. The rate of flow of water through the nozzle fitted at the end of the penstock is 2 m3s. The angle of deflection of jet is 165° when the vanes are stationary. Determine the power given by the water to the runner and also hydraulic efficiency. Take speed ratio=0.45 and Cv=1.0.
10 M

7 (a) What is draft tube? What are the functions of draft tube?
6 M
7 (b) With the help of a neat sketch, explain the component parts of Kaplan turbine.
6 M
7 (c) A Kaplan turbine produces 6000 kW under a net head of 25m with an overall efficiency of 90%. Taking the value of speed ratio as 1.6 and flow ratio as 0.5 and hub diameter as 0.35 times the outer diameter, find the diameter and speed of the turbine.
8 M

8 (a) Explain manometric efficiency, mechanical efficiency and overall efficiency of a centrifugal pump.
6 M
8 (b) Describe with sketches pumps in series and pumps in parallel.
6 M
8 (c) A centrifugal pump running at 1450 rpm discharges 710 litres per second against a head of 23 metres. If the diameter of the impeller is 250 mm and its width is 50mm find the vane angle at the outer periphery. The manometric efficiency of the pump is 75%.
8 M

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