Friction factor for a hydraulically smooth pipe at NRe = 2100 is f1. If the pipe is further smoothened (i.e., roughness is reduced), the friction factor at the same value of NRe, will_______________?

Related Mcqs:

1. In case of hydraulically smooth pipe, the resistance to flow depends only on the Reynolds number, whereas for a hydraulically rough pipe, the resistance to flow is governed by the relative roughness. Two pipes are said to have the same hydraulic roughness, when they have equal values of___________________?

   A. Relative roughness
   B. Absolute roughness
   C. Friction co-efficient for flows at equal Reynold number
   D. All A., B. & C.

2. For a given Reynolds number, in a hydraulically smooth pipe, further smoothening ____________ the friction factor?

   A. Brings about no further reduction of
   B. Increases
   C. Decreases
   D. None of these

3. What is the value of Fanning friction factor f ‘ for smooth pipe at NRe = 106 approximately ?

   A. 0.003
   B. 0.01
   C. 0.1
   D. 0.3

4. A pipe is defined as ‘hydraulically smooth’, if the friction factor_________________?

   A. Is not a function of Reynolds number
   B. For a given Reynolds number remains constant even on further smoothening of the pipe
   C. Is zero irrespective of the Reynolds number
   D. None of these

5. The friction factor for turbulent flow in a hydraulically smooth pipe______________?

   A. Depends only on Reynolds number
   B. Does not depend on Reynolds number
   C. Depends on the roughness
   D. None of these

6. A fluid (μ/ρ) = 0.01 cm2/sec is moving at critical flow condition (NRe = 2100) through a pipe of dia 3 cms. Velocity of flow is _______________ cm/sec?

   A. 7
   B. 700
   C. 7000
   D. 630

7. Consider two pipes of same length and diameter through which water is passed at the same velocity. The friction factor for rough pipe is f1 and that for smooth pipe is f2. Pick out the correct statement ?

   A. f1 = f2
   B. f1 < f2
   C. f1 > f2
   D. Data not sufficient to relate f1 & f2

8. Which of the following equations as suggested by Colebrook and White gives the increase in roughness of a new surface (ε0) with age/time (t) (where, ε = roughness of the surface after time’t’. α = a co-efficient to be experimentally determined) ?

   A. ε = ε0 + α.t
   B. ε = ε0 + α.t2
   C. ε = ε0 + α.t3
   D. ε = ε0 + α.t4

9. For turbulent flow in smooth circular pipe, the velocity distribution is a function of the distance ‘d’ measured from the wall of the pipe and the friction velocity ‘v’, and it follows a _____________ relationship?

   A. Logarithmic
   B. Linear
   C. Hyperbolic
   D. Parabolic

10. Colebrook equation for friction factor in turbulent flow is given by, f-0.5 = -4 loge [(ε/D) + (1.26/NRe √F). It reduces to Nikuradse equation for a value of (ϵ/D) equal to __________________?

    A. 0
    B. 1
    C. ∞
    D. 0.5