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 ?

Related Mcqs:

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

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

2. Drag co-efficient for flow past immersed body is the ratio of _____________ to the product of velocity head and density?

   A. Shear stress
   B. Shear force
   C. Average drag per unit projected area
   D. None of these

3. Creeping flow around a sphere is defined, when particle Reynolds number is___________________?

   A. < 2100
   B. < 0.1
   C. > 2.5
   D. < 500

4. In which of the following body shapes, the pressure drag is large compared to the friction drag ?

   A. Stream line body
   B. Two dimensional body
   C. Bluff body
   D. None of these

5. The ratio of wall drag to total drag in the Stoke’s law range is_________________?

   A. 0.5
   B. 1
   C. 1/3
   D. 2/3

6. The ratio of the wall drag to the form drag in the Stoke’s law range (for motion of spherical particles in a stationary fluid) is__________________?

   A. 0.5
   B. 1
   C. 2
   D. 0.33

7. Cd, Cc and Cv are related (for flow through an orifice) as (where, Cd = discharge co-efficient, Cc = co-efficient of contraction = (area of jet at vena-contracta/area of opening), Cv = co-efficient of velocity = (actual velocity at vena-contracta/theoretical velocity)?

   A. Cd = Cc/Cv
   B. Cd = Cc.Cv
   C. Cd = Cv/ Cc
   D. None of these

8. Which of the following relationship is valid for the equilibrium position of the float in a Rotameter? (Where, Df= Drag force on the float Bf = Buoyant force on the float Wf = Weight of the float)?

   A. Df + Bf = Wf
   B. Df = Bf + Wf
   C. Df + Bf + Wf =0
   D. None of these

9. Reynolds number for flow of water at room temperature through 2 cm dia pipe at an average velocity of 5 cm/sec is around________________?

   A. 2000
   B. 10
   C. 100
   D. 1000

10. Reynolds number for water flow through a tube of I.D. 5 cm is 1500. If a liquid of 5 centipoise viscosity and 0.8 specific gravity flows in the same pipe at the same velocity, then the pressure drop will______________________?

    A. Increase
    B. Decrease
    C. Remain same
    D. Data insufficient to predict pressure drop