4HE Fluid Mechanics - October 1996

Part A - (20 X 2 = 40 marks)

  1. The unit of specific weight of a fluid in SI system is ______________.
  2. One centipoise is equal to ______________ Pa.S.
  3. The pressure inside a soap bubble will be ______________ than the surrounding atmospheric pressure.
  4. Give an example of non-Newtonian fluid ______________.
  5. The unit of one standard atmospheric pressure is 101.32 ______________.
  6. Gauge pressure is absolute pressure ______________ atmospheric pressure.
  7. Dynamic similarity is similarity of ______________.
  8. In M, L, T system dimension of angular velocity is ______________.
  9. The density of manometric fluid used in an inverted manometer should be ______________ than the density of flowing fluid.
  10. For steady incompressible fluid flow, the continuity equation is ______________.
  11. is the equation of vorticity along ______________ axis.
  12. is the equation of a ______________ in two dimensional flow.
  13. For flow over flat plate, the critical Reynolds number is ______________.
  14. Reynolds number is the ratio of inertial force and ______________ force.
  15. Mach number is the ratio of ______________ to ______________.
  16. Cd of an orifice is always ______________ than Cc.
  17. The suppressed sharp crested weir is 0.6 m high and discharges water at a head of 1.2 m. The coefficient of discharge of the weir is ______________.
  18. The gas flow velocity through a fluidized bed should be less than or equal to ______________ velocity.
  19. Give an example of rotary pump ______________.
  20. Blowers are suitable for ______________ discharge than compressors.
  21. Part B - (5 X 12 = 60 marks)

  22. (a) Sketch stress versus strain diagram for Non-Newtonian fluid.
  23. (b) A U-tube differential mercury manometer is connected between two pipes X and Y. Pipe X contains carbon tetra chloride (sp.gr 1.594) under a pressure of 103 kN/m2 and pipe Y contains oil (sp.gr 0.8) under a pressure of 172 kN/m2. Pipe X is 2.5 m above pipe Y. Mercury level in the limb connected to pipe X is 1.5 m below the center line of pipe Y. Find the manometer reading in cm.


  24. (a) State any three dimensionless number related to fluid flow and explain their significance.
  25. (b) Explain the term "Geometric similarity" and "Kinematic similarity".

  26. (a) Determine whether the velocity components given below satisfy the equation of continuity:

  27. u = 2x2 + zy
    v = -2xy + 3y3 + 3zy
    w = -1.5z2 - 2xy - 6yz.

    (Does not satisfy the equation of continuity)

    (b) A 15 cm diameter pipe is reduced to 7.5 cm diameter through gradual contraction. At this contraction the difference in pressure between these two points is 4 cm of mercury. By neglecting losses, calculate the discharge of water.

    (0.01491 m3/sec)


  28. (a) Explain the term "Form Drag" and "Friction Drag".
  29. (b) An oil of relative density 0.92 and dynamic viscosity 0.082 Pa.S flows in an 80 mm diameter pipe. In a distance of 20 m the flow has a head loss of 2 m. Calculate (I) the mean velocity (ii) discharge (iii) shear stress at the pipe wall.

    (2.202 m/sec; 0.01107 m3/sec; 18.054 N/m2)

  30. (a) With a neat sketch explain the working principle of a Rotameter.
  31. (b) A pitot tube is inserted in a pipe of 30 cm diameter. The static pressure of the tube is 10 cm of mercury vacuum. The stagnation pressure at the center of the pipe recorded by the pitot tube is 1 N/cm2. Calculate the rate of flow of water through the pipe, if the mean velocity of flow is 0.85 times the central velocity.

    (24.626 m3/min)


  32. (a) Explain the working principle of a magnetic flow meter.
  33. (b) A rectangular weir 0.75 m high and 1.5 m long is to be used for discharging water from a tank under a head of 0.5 m. Estimate the discharge (I) when it is used as a suppressed weir (ii) when it is used as a contract weir. Use Rehbock equation for estimating Cd in both cases.

  34. Derive an expression for pressure drop in a packed bed.
  35. Or
  36. (a) Discuss the mechanism of fluidization.
  37. (b) Give some industrial applications of fluidization.

  38. (a) What are the applications of diaphragm pump?
  39. (b) Name any three positive displacement pump and explain the working principle of any one type.


  40. With a neat sketch explian the working principle of a centrifugal pump. Also explain the "Priming" of a centrifugal pump.