# Laminar Boundary Layer on a Flat Plate - MCQs with Answers

## Laminar Boundary Layer on a Flat Plate – MCQs with Answers

1. Which of the following assumptions is/are correct to obtain an analytical solution for the problem on laminar boundary layer of fluid on flat plate?

a. The fluid is incompressible
b. The fluid is in steady-state
c. The is not affected by fluid flow
d. all of the above

ANSWER: d. all of the above

2. Consider the flow of fluid in a boundary layer. Take a control volume which has a shape of a parallelopiped with dimensions (dx x dy x 1)
u = velocity of the fluid entering the control volume
v = velocity of the fluid leaving the control volume

Considering above condition, the equation

(∂u / ∂x) + (∂v / ∂y) = 0

is known as

a. continuity equation for incompressible, steady, two dimensional flow
b. continuity equation for compressible, steady, two dimensional flow
c. continuity equation for incompressible, unsteady, two dimensional flow
d. continuity equation for incompressible, steady, three dimensional flow

3. Change in momentum is

a. the result of powers acting on the surface of the control volume
b. the result of works acting on the surface of the control volume
c. the result of forces acting on the surface of the control volume
d. none of the above

ANSWER: c. the result of forces acting on the surface of the control volume

4. When the hydrodynamic boundary layer thickness (δ), which is the distance from the surface at which the local velocity (u) reaches 99% of the free-stream velocity, then

a. (δ / x) = 5 / (Rex)(1/2)
b. (δ / x) = 5 / (Rex)(2)
c. (δ / x) = 10 / (Rex)(1/2)
d. (δ / x) = 10 / (Rex)(2)