FMHM & Hydraulic chapter 3

 

Unit-3 Fluid Kinematics

1. The motion of fluid particles may be described by which of the following methods?
(a) Langrangian method
(b) Eulerain method
(c) Both (a) and (b)
(d) None of the above.
Answer C

2. In which of the following methods, the observer concentrates on a point in the fluid system?
(a) Langrangian method
(b) Eulerian method
(c) Any of the above
(d) None of the above.
Answer D

3. Normal acceleration in fluid-flow situation exists only when
(a) The flow is unsteady
(b) The flow is two-dimensional
(c) The streamlines are straight and parallel
(d) The streamlines are curved.
Answer B

4. In a steady flow the velocity
(a) Does not change from place to place
(b) At a given point does not change with time
(c) May change its direction but the magnitude remains unchanged
(d) None of the above.
Answer B

5. The flow in a pipe whose valve is being opened or closed gradually is an example of
(a) Steady flow
(b) Unsteady flow
(c) Rotational flow
(d) Compressible flow.
Answer B

6. The type of flow in which the velocity at any given time does not change with respect to space is called
(a) Steady flow
(b) Compressible flow
(c) Uniform flow
(d) Rotational flow.
Answer C

7. Flow in a pipe where average flow parameters are considered for analysis is an example of
(a) In compressible flow
(b) One-dimensional flow
(c) Two-dimensional flow
(d) Three-dimensional flow.
Answer B

8. The flow in a river during the period of heavy rainfall is
(a) Steady, non-uniform and three-dimensional
(b) Steady, uniform, two-dimensional
(c) Unsteady, uniform, three-dimensional
(d) Unsteady, non-uniform and three-dimensional.
Answer D

9. Flow between parallel plates of infinite extent is an example of
(a) One-dimensional flow
(b) Two-dimensional flow
(c) Three-dimensional flow
(d) Compressible flow.
Answer B

10. If the flow is irrational as well as steady it is known as
(a) Non-uniform flow
(b) One-dimensional flow
(c) Potential flow
(d) None of the above.
Answer C

11. High velocity flow in a conduit of large size is known as
(a) Laminar flow
(b) Turbulent flow
(c) Either of the above
(d) None of the above.
Answer B
 

12. If the Reynolds number is less than 2000, the flow in a pipe is
(a) Laminar flow
(b) Turbulent flow
(c) Transition flow
(d) None of the above.
Answer A

13. The path followed by fluid particle in motion is called a
(a) Streamline
(b) Path line
(c) Streak line
(d) None of the above.
Answer B
 

14. A....is an imaginary line within the flow so that the tangent at any point on it indicates the velocity at that point.
(a) Streak line
(b) Stream line
(c) Path line
(d) None of the above.
Answer B
 

15. A stream line is one
(a) In which stream function does not change
(b) In which the flow cannot cross the bounding surface
(c) Which has a constant area throughout its length so that the velocity remains constant.
(d) None of the above.
Answer B
 

16. ...... is a curve which gives an instantaneous picture of the location of the fluid particles which have passed through a given point.
(a) Path line
(b) Stream line
(c) Streak line
(d) None of the above.
Answer C

17. In fluid mechanics, the continuity equation is a mathematical statement embodying the principle of
(a) Conservation of momentum
(b) Conservation of mass
(c) Conservation of energy
(d) None of the above.
Answer B
 

18. An irrational flow is one in which
(a) The stream lines of flow are curved and closely spaced
(b) The fluid does not rotate as it moves along
(c) The net rotation of fluid particles about their mass centers remains zero
(d) None of the above.
Answer C

19. In a fluid-flow the stream lines are lines
(a) Along which the vorticity is zero
(b) Along which the stream function ψ = constant
(c) Which are parallel to the equipotential lines
(d) Which exist in irrotional flow only.
Answer B
 

20. ....... is defined mathematically as the line integral of the tangential velocity about a closed path (contour).
(a) Circulation
(b) Vorticity
(c) Either of the above
(d) None of the above.
Answer A

21. The concept of stream function which is based on the principle of continuity is applicable to
(a) Irrotational flow only
(b) Two-dimensional flow only
(c) Three-dimensional flow
(d) Uniform flow only.
Answer B
 

22. The motion is described as ......when the components of rotation or vorticity are zero throughout certain point of the fluid.
(a) Rotational
(b) Irrotational
(c) Either of the above
(d) None of the above.
Answer B
 

23. ........ is defined as a scalar function of space and time such that its negative derivative with respect to any direction gives the fluid velocity in that direction.
(a) Velocity potential function
(b) Stream function
(c) Circulation
(d) Vorticity.
Answer A

24. If velocity potential (φ) satisfies the Laplace equation, it represents the possible..... flow.
(a) Unsteady, compressible, rotational
(b) Steady, compressible, irrotational
(c) Unsteady, incompressible, rotational
(d) Steady, incompressible, irrotational.
Answer D

25. A flow net is a graphical representation of strea lines and equipotential lines such that these lines
(a) Intersect each other orthogonally forming curvilinear squares
(b) Intersect each other at various different angles forming irregular-shaped nets
(c) Indicate the direction and magnitude of vector
(d) None of the above.
Answer A

26. The flow-net analysis can be used to determine
(a) The stream lines and equipotential lines
(b) Quantity of seepage and upward lift pressure below hydraulic structures
(c) The efficient boundary shapes, for which the flow does not separate.
(d) The velocity and pressure distribution for given boundaries of flow (provided the velocity distribution and pressure at any reference section are known).
(e) All of the above
Answer E
 

27. What type of flow can be taken for granted in a pipe of a uniform cross-section?
a) steady
b) unsteady
c) uniform
d) non-uniform
Answer: c

28. Can the flow inside a nozzle be steady and uniform?
a) yes
b) never
c) it can be steady but never uniform
d) it can be uniform but never steady
Answer: c

29. Which of the following statements is true regarding one and two-dimensional flows?
a) Flow in a pipe is always taken as one-dimensional flow
b) Flow in a pipe is always taken as two-dimensional flow
c) Flow in a pipe is taken as one-dimensional flow when average flow parameters are considered
d) Flow in a pipe is taken as two-dimensional flow when average flow parameters are considered
Answer: c

30. Which of the following is true?
a) Flow is rotational inside the boundary layer and irrotational outside
b) Flow is irrotational inside the boundary layer and rotational outside
c) Flow is rotational both inside and outside of the boundary layer
d) Flow is irrotational both inside and outside of the boundary layer
Answer: a

31. Which of the following is true?
a) Flow is laminar inside the boundary layer and turbulent outside
b) Flow is turbulent inside the boundary layer and laminar outside
c) Flow is laminar both inside and outside of the boundary layer
d) Flow is turbulent both inside and outside of the boundary layer
Answer: a

32. “The velocity of entrance and exit through a nozzle remains the same.” Is this ever possible?
a) only if the flow is compressible
b) only if the flow is laminar
c) only if the flow is rotational
d) never possible
Answer: a

33. Three flows named as 1,2 and 3 are observed. The Reynold’s number for the three are 100, 1000 and 10000. Which of the flows will be laminar?
a) only 1
b) only 1 and 2
c) 1, 2 and 3
d) only 3
Answer: b