Laminar and Turbulent Flow: Master Fluid Dynamics Concepts

Question 1

Which parameter is NOT involved in calculating the Reynolds number?

Accepted Answer

Pipe roughness

Answer

Fluid density

Answer

Fluid velocity

Answer

Pipe diameter

Question 2

Which characteristic is NOT associated with turbulent flow?

Accepted Answer

Steady flow

Answer

High Reynolds number

Answer

Fluctuating velocities

Answer

Formation of eddies

Question 3

Which condition is most likely to induce flow separation?

Accepted Answer

Adverse pressure gradient

Answer

Smooth pipe walls

Answer

Low Reynolds number

Answer

Circular pipe cross-sections

Question 4

In laminar pipe flow, the shear stress at the pipe wall is proportional to:

Accepted Answer

Fluid viscosity

Answer

Fluid velocity

Answer

Pipe diameter

Answer

Pressure drop

Question 5

A fundamental assumption in boundary layer theory is that:

Accepted Answer

The boundary layer is thin relative to the pipe diameter

Answer

The flow is two-dimensional

Answer

The flow is incompressible

Answer

The pressure gradient is constant

Question 6

For flow in a pipe, what is the characteristic length scale used in the Reynolds number calculation?

Accepted Answer

Pipe diameter

Answer

Hydraulic radius

Answer

Boundary layer thickness

Answer

Pipe length

Question 7

What dimensionless parameter is used to characterize the ratio of inertial forces to viscous forces?

Accepted Answer

Reynolds number

Answer

Euler number

Answer

Froude number

Answer

Weber number

Question 8

What is the primary cause of flow instability leading to transition from laminar to turbulent flow?

Accepted Answer

High Reynolds number

Answer

Rough pipe surface

Answer

Temperature gradient

Answer

Flow separation

Question 9

Which dimensionless parameter is used to characterize flow regimes?

Accepted Answer

Reynolds number

Answer

Nusselt number

Answer

Mach number

Answer

Grashof number

Question 10

At low Reynolds numbers, the flow is predominantly characterized by:

Accepted Answer

Laminar and steady

Answer

Turbulent and unsteady

Answer

Compressible and supersonic

Answer

Incompressible and subsonic

Question 11

Which of the following statements about the boundary layer is true?

Accepted Answer

It is the region near the surface where viscous effects are significant.

Answer

It is independent of the flow velocity.

Answer

It is only present in laminar flows.

Answer

It has a constant thickness throughout the flow domain.

Question 12

In a pipe flow, the maximum velocity is located:

Accepted Answer

At the center of the pipe

Answer

At the walls of the pipe

Answer

Halfway between the center and the walls

Answer

At the entrance of the pipe

Question 13

Which of the following is NOT a consequence of turbulence?

Accepted Answer

Smoother flow

Answer

Increased drag and heat transfer

Answer

Higher energy dissipation

Answer

Enhanced mixing

Question 14

The Navier-Stokes equations govern:

Accepted Answer

Both laminar and turbulent flow

Answer

Laminar flow only

Answer

Turbulent flow only

Answer

Neither laminar nor turbulent flow

Question 15

The concept of Prandtl's mixing length is used to model:

Accepted Answer

Turbulent flow

Answer

Laminar flow

Answer

Boundary layer flow

Answer

Compressible flow

Question 16

How do fluid properties influence the transition from laminar to turbulent flow in a pipe?

Accepted Answer

Viscosity and density affect the Reynolds number, which determines the flow regime.

Answer

Only viscosity affects the transition from laminar to turbulent flow.

Answer

Fluid properties do not influence the transition from laminar to turbulent flow.

Question 17

In laminar flow, the velocity profile is characterized by a:

Accepted Answer

Parabolic shape

Answer

Logarithmic variation

Answer

Exponential decay

Answer

Linear distribution

Question 18

Reynolds number is a dimensionless parameter that quantifies the relative significance of:

Accepted Answer

Inertial forces to viscous forces

Answer

Gravitational forces to viscous forces

Answer

Surface tension forces to viscous forces

Answer

Pressure forces to viscous forces

Question 19

Transition from laminar to turbulent flow occurs when the Reynolds number:

Accepted Answer

Exceeds a critical value

Answer

Is equal to a critical value

Answer

Falls below a critical value

Answer

Is independent of a critical value

Question 20

In turbulent flow, the velocity profile is generally:

Accepted Answer

Flatter than in laminar flow

Answer

Steeper than in laminar flow

Answer

Identical to that in laminar flow

Question 21

The boundary layer is a region near a solid surface where the:

Accepted Answer

Velocity gradient is significant

Answer

Velocity is zero

Answer

Fluid properties are constant

Answer

Pressure gradient is negligible

Question 22

A consequence of turbulent flow in pipes is:

Accepted Answer

Increased pressure drop

Answer

Reversed pressure drop

Answer

Decreased pressure drop

Answer

No change in pressure drop