Sathyabama University 2008 B.E Civil Engineering Mechanics of Fluids - II - Question Paper
SATHYABAMA UNIVERSITY
(Established under section 3 of UGC Act, 1956)
Course & Branch: B.E - CIVIL (Part Time)
Title of the paper: Mechanics of Fluids - II
Semester: II Max. Marks: 80
Sub.Code: 620PT202 (2007/2007 JAN) Time: 3 Hours
Date: 14-05-2008 Session: FN
PART A (10 x 2 = 20)
Answer All the Questions
1. Explain the term dimensionally homogeneous equation.
2. State Buckinghams p - theorem.
3. What do you understand by the terms boundary layer and boundary layer theory?
4. What are the different methods of preventing separation of boundary layers?
5. Define the terms: Hydraulic gradient line and Total energy line.
6. Differentiate between major loss and minor loss in pipes.
7. Differentiate between laminar and turbulent flow.
8. Explain the terms: hydraulic mean depth and wetted perimeter.
9. Differentiate between turbines and pumps.
10. What is priming? Why it is necessary?
PART B (5 x 12 = 60)
Answer All the Questions
11. The variables controlling the motion of a floating vessel through water are the drag force F, the speed V, the length L, the density r, the dynamic viscosity m and the acceleration due to gravity g. Derive an expression for F by dimensional analysis.
(or)
12. A 1:20 model of a flying boat is towed through water. The prototype is moving in sea-water of density 1024kg/m3 at a velocity of 15m/s. Find the corresponding speed of the model. Also determine the resistance due to waves on model, if the resistance due to waves of prototype is 500N.
13. (a) What do you mean by boundary layer separation?
(b) What is the effect of pressure gradient on
boundary layer
separation?
(or)
14. A thin plate is moving in still atmospheric air at a velocity of 4m/s. The length of the plate is 0.5m and width 0.4m. Calculate the thickness of the boundary layer at the end of the plate and drag force on one side of the plate. Take density of air as 1.25kg/m3 and kinematic viscosity 0.15 strokes.
15. Find the diameter of a pipe of length 2500m when the rate of flow of water through the pipe is 0.25m3/s and head lost due to friction is 5m. Take C = 50 in Chezys formula.
(or)
16. A horizontal pipe of diameter 400mm is suddenly contracted to a diameter 200mm. The pressure intensities in the larger and smaller pipe are given as 14.715N/cm2 and 12.73N/cm2 respectively. If Cc = 0.62, find the loss of head due to contraction. Also determine the rate of flow of water.
17. Find the discharge through a rectangular channel 3m wide, having depth of water 2m, and bed slope as 1 in 1500. Take the value of K = 2.36 in Bazins formula, and N = 0.012 in Mannings formula.
(or)
18. The discharge of water through a rectangular channel of width 6m, is 18m3/s when depth of flow of water is 2m. Calculate: (i) specific energy of the flowing water. (ii) critical depth and critical velocity and (iii) value of minimum specific energy.
19. Find the rise in pressure in the impeller of a centrifugal pump through which the water is flowing at the rate of 15 litre/s. The internal and the external diameter of the impeller are 20cm and 40cm respectively. The widths of the impeller at the inlet and outlet are 1.6cm and 0.8cm respectively. The pump is running at 1200rpm. The water enters the impeller radially at inlet and impeller vane angle at outlet is 30. Neglect loss through the impeller.
(or)
20. A Kaplan turbine runner is to be designed to develop 7357.5 kW shaft power. The net available head is 10m. Assume that the speed ratio is 0.6. If the overall efficiency is 70% and the diameter of the boss is 0.4 times the runner, find the diameter of the runner, its speed and specific speed.
| Earning: Approval pending. |
