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

3. 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

4. The shear stress distribution for a fluid flowing in between the parallel plates, both at rest, is_______________?

   A. constant over the cross section
   B. parabolic distribution across the section
   C. zero at the mid plane and varies linearly with distance from mid plane
   D. zero at plates and increases linearly to midpoint

5. 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

6. The maximum thickness of boundary layer in a pipe of radius r is____________________?

   A. 0
   B. r/2
   C. r
   D. 2r

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. When time of closure tc = L/v0 (where L is length of pipe and v0 is speed of pressure wavE., the portion of pipe length subjected to maximum head is__________________?

   A. L/4
   B. L/3
   C. L/2
   D. L

9. The length of a pipe is 1 km and its diameter is 20 cm. If the diameter of an equivalent pipe is 40 cm, then its length is_____________________?

   A. 32 km
   B. 20 km
   C. 8 km
   D. 4 km

10. 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