31. Which of the following velocity potentials satisfies continuity equation ?
A. x2y
B. x2-y2
C. cosx
D. x2 + y2
✅ The correct answer is option B.
Fluid Mechanics MCQs
32. If x is the distance from leading edge, then the boundary layer thickness in laminar flow varies as________________?
A. x
B. x
C. x
D. x/7
✅ The correct answer is option A.
33. Coefficient of velocity for Borda’s mouth piece running full is________________?
A. 0.611
B. 0.707
C. 0.855
D. 1.00
✅ The correct answer is option B.
34. A right circular cylinder open at the top is filled with liquid and rotated about its vertical axis at such a speed that half the liquid spills out, then the pressure intensity at the center of bottom is___________________?
A. zero
B. one-fourth its value when cylinder was full
C. one-half its value when cylinder was full
D. cannot be predicted from the given data
✅ The correct answer is option A.
35. A fluid of kinematic viscosity 0.4 cm2/sec flows through a 8 cm diameter pipe. The maximum velocity for laminar flow will be__________________?
A. less than 1 m/sec
B. 1 m/sec
C. 1.5 m/sec
D. 2 m/sec
✅ The correct answer is option B.
36. Centre of buoyancy always_________________?
A. coincides with the centre of gravity
B. coincides with the centroid of the volume of fluid displaced
C. remains above the centre of gravity
D. remains below the centre of gravity
✅ The correct answer is option B.
37. If the dynamic viscosity of a fluid is 0.5 poise and specific gravity is 0.5, then the kinematic viscosity of that fluid in stokes is__________________?
A. 0.25
B. 0.50
C. 1.0
D. none of the above
✅ The correct answer is option C.
38. The wake_______________?
A. always occurs before a separation point
B. always occurs after a separation point
C. is a region of high pressure intensity
D. none of the above
✅ The correct answer is option B.
39. The speed of a pressure wave through a pipe depends upon________________?
A. the length of pipe
B. the viscosity of fluid
C. the bulk modulus for the fluid
D. the original head
✅ The correct answer is option C.
40. The value of friction factor ‘f’ for smooth pipes for Reynolds number 106 is approximately equal to________________?
A. 0.1
B. 0.01
C. 0.001
D. 0.0001
✅ The correct answer is option B.