At low Reynolds number______________?

Related Mcqs:

1. As the velocity V and thus the Reynolds number of a flow past a sphere increases from very low value, the drag force for Re << 1 ?

   A. Increases linearly with V
   B. Decreases linearly with V
   C. Decreases as V2
   D. None of these

2. In the low Reynolds number region, the drag force on a sphere is proportional to_______________?

   A. V
   B. V2
   C. V4
   D. V0.5

3. Which of the following equations applies to the fluid flow through a packed bed for very large Reynolds number ?

   A. Fanning equation
   B. Blake-Plummer equation
   C. Hagen-Poiseuille equation
   D. Kozeny-Carman equation

4. The value of critical Reynolds number for pipe flow is_________________?

   A. 1,300
   B. 10,000
   C. 100,000
   D. None of these

5. 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

6. At high Reynolds number_________________?

   A. Inertial forces control and viscous forces are unimportant
   B. Viscous forces predominate
   C. Inertial forces are unimportant and viscous forces control
   D. None of these

7. Laminar flow of a Newtonian fluid ceases to exist, when the Reynolds number exceeds___________________?

   A. 4000
   B. 2100
   C. 1500
   D. 3000

8. 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.

9. A spherical particle is falling slow in a viscous liquid such that Reynolds number is less than 1. Which statement is correct for this situation ?

   A. Inertial and drag forces are important
   B. Drag, gravitational and buoyancy forces are important
   C. Drag force and gravitational forces are important
   D. None of the above

10. Which of the following is the „Blasius equation‟, relating friction factor to the Reynolds number ?

    A. f = 0.079.NRe-0.25
    B. f-0.5 = 4.07 loge (NRef)-0.6
    C. Both ‘a’ and ‘b’
    D. None of these