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

Related Mcqs:

1. The boundary layer thickness at a distance of l m from the leading edge of a flat plate, kept at zero angle of incidence to the flow direction, is O.l cm. The velocity outside the boundary layer is 25 ml sec. The boundary layer thickness at a distance of 4 m is__________________?

   A. 0.40 cm
   B. 0.20 cm
   C. 0.10 cm
   D. 0.05 cm

   Assume that boundary layer is entirely laminar

2. The distance from pipe boundary, at which the turbulent shear stress is one-third die wall shear stress, is_______________?

   A. 1/3 R
   B. 1/2 R
   C. 2/3 R
   D. 3/4R

   where R is the radius of pipe

3. The boundary layer thickness in turbulent flow varies as______________?

   A. x”7
   B. x,/2
   C. x4/5
   D. x3/5

   where x is the distance from leading edge

4. 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

5. 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

6. The eddy viscosity for turbulent flow is______________?

   A. a function of temperature only
   B. a physical property of the fluid.
   C. dependent on the flow
   D. independent of the flow

7. With the same cross-sectional area and immersed in same turbulent flow, the largest total drag will be on__________________?

   A. a circular disc of plate held normal to flow
   B. a sphere
   C. a cylinder
   D. a streamlined body

8. 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

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

   A. 16/Re
   B. 32/ Re
   C. 64/ Re
   D. none of the above where R,, is Reynolds number

10. 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