Critical velocity in a pipe flow_________________?

Related Mcqs:

1. A pipe has a porous section of length L as shown in the figure. Velocity at the start of this section of V0. If fluid leaks into the pipe through the porous section at a volumetric rate per unit area q(x/L)2, what will be axial velocity in the pipe at any „x‟? Assume incompressible one dimensional flow i.e., no gradients in the radial direction ?

   A. VX = V0 + q (x3/L2D)
   B. VX = V0 + ⅓q (x3/L2)
   C. VX = V0 + 2q (x2/LD)
   D. VX = V0 + (4/3) q (x3/L2D)

2. The pressure drop per unit length of pipe incurred by a fluid ‘X’ flowing through pipe is Δp. If another fluid ‘Y’ having both the specific gravity & density just double of that of fluid ‘X’, flows through the same pipe at the same flow rate/average velocity, then the pressure drop in this case will be__________________?

   A. Δp
   B. 2Δp
   C. Δp2
   D. Δp/2

3. The velocity profile exhibited by laminar flow of Newtonian fluids is such that the velocity distribution w.r.t. radius of the circular pipe is a/an ______________ with the apex at the centre line of the pipe?

   A. Hyperbola
   B. Parabola
   C. Semi-circle
   D. Semi-ellipse

4. A pipe of I.D. 4 m is bifurcated into two pipes of I.D. 2 m each. If the average velocity of water flowing through the main pipe is 5 m/sec, the average velocity through the bifurcated pipes is__________________?

   A. 20 m/sec
   B. 10 m/sec
   C. 5 √2 m/sec
   D. 5 m/sec

5. For turbulent flow in smooth circular pipe, the velocity distribution is a function of the distance ‘d’ measured from the wall of the pipe and the friction velocity ‘v’, and it follows a _____________ relationship?

   A. Logarithmic
   B. Linear
   C. Hyperbolic
   D. Parabolic

6. What is the ratio of the velocity at the axis of the pipe to the mean velocity of flow in case of pipe flow under viscous condition ?

   A. 0.5
   B. 0.67
   C. 1
   D. 2

7. Boundary layer exists in flow_________________?

   A. Of real fluids
   B. Over flat surfaces only
   C. In pipes only
   D. Of ideal fluids only

8. A fluid (μ/ρ) = 0.01 cm2/sec is moving at critical flow condition (NRe = 2100) through a pipe of dia 3 cms. Velocity of flow is _______________ cm/sec?

   A. 7
   B. 700
   C. 7000
   D. 630

9. For laminar flow of Newtonian fluid in a circular pipe, the velocity distribution is a function of the distance ‘d’ measured from the centre line of the pipe, and it follows a ______________ relationship?

   A. Logarithmic
   B. Parabolic
   C. Hyperbolic
   D. Linear

10. Consider two pipes of same length and diameter through which water is passed at the same velocity. The friction factor for rough pipe is f1 and that for smooth pipe is f2. Pick out the correct statement ?

    A. f1 = f2
    B. f1 < f2
    C. f1 > f2
    D. Data not sufficient to relate f1 & f2