Question

Given that, as flow takes place between two parallel static plates, the velocity midway between the plates is 2 m/s, the Reynolds number is 1200 and the distance between the plates is 10 cm, which of the following statements are true?

1. The velocity of the boundary is 1 m/s.

$2.{\text{The rate of flow is 0.1 m}}^3\text{/s/metre width.}$

3. The flow is turbulent.

4. The energy correction factor is 2.0.

Select the correct answer using the codes given below:

• A. 2 and 3
• B. 2 and 4
• C. 1 and 3
• D. 1, 2, 3 and 4

Answer 1

The correct option is A 2 and 3

As the plates are stationary so velocity at boundary = 0.

$\text{The critical Reynolds number for flow between two stationary parallel plates is 1000. So flow is turbulent. The energy correction factor for laminar flow is}\alpha =\mathrm{1.54.}$

In the case of turbulent flow it will be less than 1.54. So statements 1 and 4 are wrong.