Which of the following statements is correct ?

A. Lower critical Reynolds number is of no practical significance in pipe flow problems.
B. Upper critical Reynolds number is significant in pipe flow problems.
C. Lower critical Reynolds number has the value 2000 in pipe flow
D. Upper critical Reynolds number is the number at which turbulent flow changes to laminar flow

Related Mcqs:

The correct relationship among displacement thickness d, momentum thickness m and energy thickness e is_________________?
A. d > m > e
B. d > e > m
C. e > m > d
D. e > d > m
Select the correct statement?
A. The absolute roughness of a pipe de-creases with time
B. A pipe becomes smooth after using for long time
C. The friction factor decreases with time
D. The absolute roughness increases with time
The continuity equation pi V,A,= p2V2A2 is based on the following assumption regarding flow of fluid______________?
A. steady flow
B. uniform flow
C. incompressible flow
D. frictionless flow
where pi and p2 are mass densities
Which of the following is used to measure the discharge ?
A. current meter
B. venturimeter
C. pitot tube
D. hotwire anemometer
In which of the following the friction drag is generally larger than pressure drag?
A. a circular disc or plate held normal to flow
B. a sphere
C. a cylinder
D. an airfoil
Which of the following has highest coefficient of discharge ?
A. sharp edged orifice
B. venturimeter
C. Borda’s mouthpiece running full
D. CipoUetti weir
Which of the following velocity potentials satisfies continuity equation ?
A. x2y
B. x2-y2
C. cosx
D. x2 + y2
Which of the following is an incorrect statement ?
A. Coefficient of contraction of a venturimeter is unity
B. Flow nozzle is cheaper than venturimeter but has higher energy loss
C. Discharge is independent of orientation of venturimeter whether it is horizontal, vertical or inclined
D. None of the above statement is correct.
The total pressure on a plane surface inclined at an angle 9 with the horizontal is equal to_______________?
A. PA
B. pA sin 9
C. pA cos 9
D. pA tan 9
where p is pressure intensity at centroid of area and A is area of plane surface
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