ANNA UNIVERSITY QUESTION PAPERS
B.E. DEGREE EXAMINATION – IV Semester
Civil Engineering and Computer based Construction
HYDRAULICS AND HYDRAULIC MACHINERY
Time : Three hours Maximum : 100 marks
Answer ALL questions.
PART A — (10 ´ 2 = 20 marks)
1. Distinguish between Venturimeter and Orifice meter.
2. What is Vena Contracta and draw a sketch?
3. List the possible types of flow through open channel with respect to space and time.
4. Define critical and normal depth in a rectangle open channel.
5. Draw neat sketch of hydraulic gradient line and total gradient line in case of flow through pipe as well as flow through open channel.
6. Write short notes on Reynold’s number.
7. Where and when do the water hammer in a pipe flow?
8. What is equivalent pipe and write the equation for equivalent diameter?
9. Write the types of hydraulic turbine.
10. What is the purpose of providing Governing Mechanism in a turbine?
PART B — (5 ´ 16 = 80 marks)
11. (i) What is specific energy in a open channel flow? (4)
(ii) Determine the normal depth in a trapezoidal channel with bottom width 40 m and side slope 2 horizontal : 1 vertical when it carries 60 m3/s of water discharge at a bed slope of 1 in 5000. Assume Manning’s roughness coefficient as 0.015. (12)
12. (a) (i) Compare between Current meter and Anemo meter based on used for measurement of fluid flow. (6)
(ii) Water flows over a rectangular weir 1 m wide at a depth of 15 cm and afterwards passes through a triangular right angled weir. Find the depth of water through the triangular weir. The discharge coefficient for the rectangular and triangular weirs are 0.62 and 0.59 respectively. (10)
(b) (i) What are all the types of weir based on shape and flow over the weir? (4)
(ii) Oil of specific gravity 0.85 issues from a 5 cm diameter orifice under a pressure of 1.2 kg/cm2 (gauge). The diameter of the jet at vena contracta is 4.0 cm and the discharge is 1.2 m3/minute. What is the coefficient of velocity? (12)
13. (a) (i) List out various types of Gradually Varied Flow (GVF) profiles with neat sketch showing critical and normal depth line along with profile? (8)
(ii) Derive from basic principle the Chezy’s and Manning’s formula for uniform flow through open channel. (8)
(b) (i) What is hydraulic jump and list its types of jump? (6)
(ii) Determine approximate water surface slope (m per km) at a point in a rectangular channel in which the discharge is 0.84 m3/s, the bed width is 3 m, the depth of flow is 0.75 m and the bed slope is 0.15 m per km. Assume C in Chezy’s formula as 55 and take energy coefficient alpha equal to unity. (10)
14. (a) (i) Derive from basic principle Hagen Poiseuille equation for laminar flow through circular pipe. (10)
(ii) A sudden enlargement of water line from a diameter 0.25 m to
0.48 m, the hydraulic gradient line rises by 0.01 m. Estimate the quantity of water flowing in the pipe line. (6)
(b) Two reservoirs are connected by a pipe line which rises above the level of the higher reservoir. The difference in the water level of the two reservoirs is 12.5 m. What will be the highest point of the siphon above water surface level in the higher tank if the length of the pipe leading up to this point is 450 m, the total length of the pipeline is 915 m and the diameter of the pipe is 0.30 m? Take friction factor (f) in the Darcy equation for head loss in the pipe as 0.04. The siphon pipe is run full. Assume that the separation will occur if the absolute pressure in the pipe falls below 2.44 m of water. (16)
15. (a) (i) What is specific speed of the turbine and runaway speed of the turbine? (4)
(ii) Draw neat sketch of the draft tube in reaction turbine and explain briefly the working principle of the draft tube. (6)
(iii) A turbine runner discharges water into a draft tube at a velocity of 6 m/s and the velocity at the tube exit is 1.25 m/s. The tail water is 5 m below the entrance of the draft tube and losses in the draft tube are 0.01 m. Determine the pressure head at the draft tube entrance, and the draft tube efficiency. (6)
(b) (i) Draw the characteristic curves of a Pelton wheel turbine for speed variation under constant head and discharge. (8)
(ii) An inward flow reaction turbine of inlet diameter 1.2 m operates under a head of 150 m and requires a discharge of 6 m3/s at a rotational speed of 400 rpm. The guide vane angle is 20 degree and the water leaves the blade radially. If the runner is 10 cm wide at the inlet. Calculate the torque and power applied to the shaft. (8)