# Fluid Mechanics Questions and Answers – Turbulent Boundary Layer on a Flat Plate

This set of Fluid Mechanics Multiple Choice Questions & Answers (MCQs) focuses on “Turbulent Boundary Layer on a Flat Plate”.

1. The main property that affects a boundary layer is__________
a) Temperature
b) Pressure
c) Viscosity
d) Surface tension

Explanation: A boundary layer is an important concept that refers to the layer of fluid. The fluid that is in the immediate vicinity of a bounding surface. The main property that affects a boundary layer is viscosity.

2. The layer that is influenced by a planetary boundary is called______
a) Atmospheric boundary layer
b) Lithosphere
c) Troposphere
d) Hydrosphere

Explanation: The planetary boundary layer is also called as atmospheric boundary layer(ABL). It is the lowest part of the atmosphere. The behaviour of ABL is directly influenced by its contact with the planetary surface.

3. What is the other name for Stoke’s boundary layer?
a) Momentum boundary layer
b) Atmospheric boundary layer
c) Oscillatory boundary layer
d) Thermal boundary layer

Explanation: Stoke’s boundary layer is also called as Oscillatory boundary layer. It is a boundary layer that is close to a solid wall. It moves in an oscillatory motion. It arrested by a viscous force acting in the opposite direction.

4. Eddy viscosity is a turbulent transfer of_________
a) Fluid
b) Heat
c) Momentum
d) Pressure

Explanation: Eddy viscosity is a turbulent transfer of momentum by eddies. It gives rise to an internal fluid friction. It is in analogous to the action of molecular viscosity in laminar fluid flow. Eddy viscosity takes place on a large scale.

5. The laminar boundary layer is a _________
a) Smooth flow
b) Rough flow
c) Uniform flow
d) Random flow

Explanation: For a laminar boundary layer the fluid moves in a very smooth flow. The laminar flow creates less skin friction drag. It is a less stable flow. The laminar boundary layer has got an increase in its thickness.
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6. The turbulent boundary layer is a _________
a) Non-uniform with swirls
b) Uniform
c) Less stable
d) Smooth

Explanation: For a turbulent boundary layer the fluid moves in different direction producing swirls. It has more skin friction drag than that of laminar boundary layer. It is more stable when compared to laminar.

7. How do we measure the flow rate of liquid?
a) Coriolis method
c) Conveyor method
d) Ionization method

Explanation: Coriolis concept of measurement of fluid takes place through the rotation with the reference frame. It is an application of the Newton’s Law. The device continuously records, regulates and feeds large volume of bulk materials.

8. How does a turbulent boundary layer produce swirls?
a) Due to random motion
b) Collision of molecules
c) Due to eddies
d) Due to non-uniform cross section

Explanation: For a turbulent boundary layer the fluid moves in different direction producing swirls. It produces swirls due to the presence of eddies. The smooth laminar boundary layer flow breaks down and transforms to a turbulent flow.

9. Define Viscosity.
a) Resistance to flow of object
b) Resistance to flow of air
c) Resistance to flow of fluid
d) Resistance to flow of heat

Explanation: Viscosity is developed due to the relative motion between two surfaces of fluids at different velocities. It happens due to the shear stress developed on the surface of the fluid.

10. The continuity equation of two- dimensional steady incompressible flow is _______
a) $$\frac{∂u}{∂x} + \frac{∂u}{∂y}$$ = 0
b) $$\frac{∂u}{∂x} + \frac{∂u}{∂y}$$ = 1
c) $$\frac{∂u}{∂x} * \frac{∂u}{∂y}$$ = 0
d) 0

Explanation: The continuity equation of two- dimensional steady incompressible flow is $$\frac{∂u}{∂x}+\frac{∂u}{∂y}$$ = 0. It is in accordance with the Navier- Stokes equations for a two- dimensional steady incompressible flow in cartesian coordinates.

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