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 __________________?

Related Mcqs:

1. 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_______________?

   A. Increase
   B. Decrease
   C. Remain unchanged
   D. Increase or decrease depending on the pipe material

2. The equation relating friction factor to Reynold number, f-0.5 = 4 loge (NRe/√f)-0.4, is called the _____________ equation?

   A. Nikuradse
   B. Von-Karman
   C. Blasius
   D. Colebrook

3. Bernoulli’s equation for fluid flow is derived following certain assumptions. Out of the assumptions listed below, which set of assumptions is used in derivation of Bernoulli’s equation? A. Fluid flow is frictionless & irrotational. B. Fluid flow is steady. C. Fluid flow is uniform & turbulent. D. Fluid is compressible. E. Fluid is incompressible ?

   A. A, C, D
   B. B, D, E
   C. A, B, E
   D. A, D, E

4. The equation f-0.5 = 4.07 loge (NRe √f)-0.6 is called the ____________?

   A. Colebrook formula
   B. Von-Karman equation
   C. Fanning equation
   D. None of these

5. Fanning friction factor is equal to (where, fB = Blasius friction factor) ?

   A. fB/4
   B. fB/2
   C. 4fB
   D. 2fB

6. If Blasius or Darcy friction factor is ‘f1’ then the Fanning friction factor is equal to____________________?

   A. f1/4
   B. 4f2
   C. 2f1
   D. f1/2

7. 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

8. In turbulent flow, a rough pipe has the same friction factor as a smooth pipe____________________?

   A. In the zone of complete turbulence
   B. When the roughness projections are much smaller than the thickness of the laminar film
   C. Everywhere in the transition zone
   D. When the friction factor is independent of the Reynold’s number

9. 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

10. If three pipes of different diameters, lengths & friction factors are connected in parallel, then (where, Q = flow rate, V= fluid velocity f = friction factor). ?

    A. Q = Q1 + Q2 + Q3
    B. V1 = V2 = V3
    C. Q1 = Q2 = Q3
    D. f = f1 + f2 + f3