For laminar flow in circular pipes, the Darcy’s friction factor f is equal to_________________?

Related Mcqs:

1. For laminar flow in a pipe of circular cross-section, the Darcy’s friction factor f is________________?

   A. directly proportional to Reynolds number and independent of pipe wall roughness
   B. directly proportional to pipe wall roughness and independent of Reynolds number
   C. inversely proportional to Reynolds number and indpendent of pipe wall roughness
   D. inversely proportional to Reynolds number and directly proportional to pipe wall roughness

2. The ratio of average velocity to maximum velocity for steady laminar flow in circular pipes is_______________?

   A. 1/2
   B. 2/3
   C. 3/2
   D. 2

3. 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

4. The depth ‘d’ below the free surface at which the point velocity is equal to the average velocity of flow for a uniform laminar flow with a free surface, will be_________________?

   A. 0.423 D
   B. 0.577 D
   C. 0.223 D
   D. 0.707 D

   where D is the depth of flow

5. The velocity distribution for laminar flow through a circular tube__________________?

   A. is constant over the cross-section
   B. varies linearly from zero at walls to maximum at centre
   C. varies parabolically with maximum at the centre
   D. none of the above

6. 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

7. 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

8. For hydro-dynamically smooth boundary, the friction coefficient for turbulent flow is_______________?

   A. constant
   B. dependent only on Reynolds number
   C. a function of Reynolds number and relative roughness
   D. dependent on relative roughness only

9. If the elevation of hydraulic grade line at the junction of three pipes is above the elevation of reservoirs B and C and below reservoir A, then the direction of flow will be___________________?

   A. from reservoir A to reservoirs B and C
   B. from reservoir B to reservoirs C and A
   C. from reservoir C to reservoirs A and B
   D. unpredictable

10. The distance y from pipe boundary, at which the point velocity is equal to average velocity for turbulent flow, is________________?

    A. 0.223 R
    B. 0.423 R
    C. 0.577 R
    D. 0.707 R

    where R is radius of pipe