SPSC 2011 Assistant Engineer / Assistant Executive Engineer (Civil) BPS-17, Engineers Cadre CCE (2011) — Hydraulics & Fluid Mechanics Paper

Assistant Engineer / Assistant Executive Engineer (Civil) BPS-17, Engineers Cadre CCE (2011) — Hydraulics & Fluid Mechanics. Combined Competitive Examination for Engineers Cadre · Tuesday 22 March 2011, 10:00 am to 1:00 pm · Max marks 100. Attempt any 05 questions.

1. 1(a) What advantages can be achieved with the formation of a hydraulic jump along a hydraulic structure? (05) (b) Derive a relationship for the depth of water after the formation of hydraulic jump. (15)

2. 2What do you mean by the "most economical channel cross-section"? Show that for a circular culvert of diameter D the velocity of flow will be a maximum when the depth of flow h at the centre is 0.81 D. Use the Chezy formula. (20)

3. 3Discuss the uses of: (i) Dimensional analyses; and (ii) Hydraulic similarity, in the field of Fluid mechanics and Hydraulics. (20)

4. 4(a) Express the merits due to which a Centrifugal pump can be preferred over a Reciprocating pump. (08) (b) How the available energy of water is used to produce hydropower using an Impulse turbine, describe? (12)

5. 5(a) Find the total pressure and the position of the centre of pressure on one side of an immersed rectangular plate, 6 ft long and 3 ft wide, when the plane of the plate makes an angle of 60° with the surface of the water and the 3 ft edge of the plate is parallel to, and at a depth of 2½ ft below the surface level of the water. (10) (b) Calculate the density, specific weight and specific volume of air at 120°F and 30 psia. (10)

6. 6A single-acting reciprocating pump has a piston area of 1.5 ft² and a stroke of 12 in. The cross sectional area of delivery pipe is 0.3 ft² and the water is lifted through a total height of 40 ft. If the speed of the pump is 60 r.p.m., and the actual quantity of water lifted 550 gal/min, find the slip, the coefficient of discharge, and the theoretical horse power required to drive the pump. (20)

7. 7(a) A jet of water 1 in. in diameter has a velocity of 60 ft/sec. Find the horse power of the jet. (10) (b) A Venturi meter has an enlarged end of 2 ft² area and a throat area of 0.25 ft². The coefficient of meter is 0.97. If the Venturi head is 9 in. of water, find the quantity of water flowing. (10)

8. 8A masonry dam of rectangular section 20 ft high and 10 ft wide has the water level with its top. Find (1) the total pressure on 1 ft length of the dam; (2) the height of the centre of pressure; (3) the point at which resultant cuts the base. The weight of 1 ft³ of masonry is 110 lb. (20)