Fluid Kinematics: Master Fluid Motion Concepts for Mechanical Engineers

Question 1

Which of the following is the SI unit of kinematic viscosity?

Accepted Answer

Meter-squared per second

Answer

Pascal-second

Answer

Newton-meter

Answer

Joule-second

Question 2

A fluid flow is considered steady if its properties at a given point:

Accepted Answer

Do not change with time

Answer

Change with time

Answer

Change with distance

Answer

Do not change with distance

Question 3

Which of the following correctly describes a pathline in a fluid flow?

Accepted Answer

Line connecting positions of a fluid particle at different instants

Answer

Line tangent to velocity vector at a specific point

Answer

Line perpendicular to velocity vector at a specific point

Answer

Line representing path of a floating object

Question 4

The continuity equation, expressed differentially, embodies the principle of:

Accepted Answer

Conservation of mass

Answer

Conservation of momentum

Answer

Conservation of energy

Answer

Conservation of angular momentum

Question 5

Which of the following is necessary for potential flow?

Accepted Answer

Irrotational flow

Answer

Incompressible flow

Answer

Viscous flow

Answer

Turbulent flow

Question 6

The Reynolds number is a dimensionless parameter representing the:

Accepted Answer

Ratio of inertial forces to viscous forces

Answer

Ratio of pressure forces to viscous forces

Answer

Ratio of gravitational forces to viscous forces

Answer

Ratio of surface tension forces to viscous forces

Question 7

The velocity field of a fluid is defined as:

Accepted Answer

A mathematical function that describes the velocity of a fluid particle at any given point and time

Answer

The rate of change of displacement of a fluid particle

Answer

The gradient of pressure

Answer

The divergence of velocity

Question 8

The continuity equation states that:

Accepted Answer

The mass of fluid flowing into a control volume is equal to the mass of fluid flowing out of the control volume

Answer

The velocity of a fluid is constant

Answer

The pressure of a fluid is constant

Answer

The density of a fluid is constant

Question 9

Which of the following is **NOT** an assumption of the continuity equation?

Accepted Answer

The fluid flow is irrotational

Answer

The fluid is incompressible

Answer

The fluid flow is steady

Answer

The fluid has a constant density

Question 10

Which of the following is **not** a defining trait of fluid flow?

Accepted Answer

Exclusively laminar

Answer

Persistent at any given point in time

Answer

Characterizable by velocity and pressure fields

Answer

Obedient to the principles of conservation (mass, momentum, energy)

Question 11

The continuity equation for an incompressible fluid implies that:

Accepted Answer

The mass flow rate into a control volume equals the mass flow rate out of it.

Answer

The fluid velocity is constant throughout the control volume.

Answer

The fluid pressure is constant throughout the control volume.

Answer

The fluid temperature is constant throughout the control volume.

Question 12

A fluid particle moves in a circular path at a constant speed. What can be said about its acceleration?

Accepted Answer

It is directed toward the circle's center.

Answer

It is zero.

Answer

It is directed away from the circle's center.

Answer

It is tangential to the circle.

Question 13

A streamline is a line that is:

Accepted Answer

Tangent to the velocity vector at every point

Answer

Perpendicular to the velocity vector at every point

Answer

Connects points of equal pressure

Answer

Connects points of equal velocity magnitude

Question 14

The acceleration vector of a fluid particle in a flow field can be:

Accepted Answer

Parallel or perpendicular to the velocity vector

Answer

Parallel to the velocity vector

Answer

Perpendicular to the velocity vector

Answer

Always zero

Question 15

The velocity profile of a fluid flowing in a circular pipe is:

Accepted Answer

Parabolic

Answer

Linear

Answer

Exponential

Answer

Sinusoidal

Question 16

The Reynolds number is a dimensionless quantity that is used to:

Accepted Answer

Characterize the type of flow regime

Answer

Calculate the drag force on a fluid

Answer

Determine the pressure drop in a pipe

Answer

Predict the flow rate of a fluid

Question 17

The energy equation for a fluid flowing in a pipe includes the following terms:

Accepted Answer

Pressure head, velocity head, and elevation head

Answer

Pressure head, shear stress head, and velocity head

Answer

Pressure head, gravitational head, and friction head

Answer

Pressure head, kinetic energy, and potential energy

Question 18

Which of the following is NOT a type of fluid flow?

Accepted Answer

Thermal flow

Answer

Turbulent flow

Answer

Laminar flow

Answer

Compressible flow

Question 19

The velocity field of a fluid is given by V = (u, v, w). What is the magnitude of the acceleration field at a point where u = 2 m/s, v = 3 m/s, and w = 4 m/s?

Accepted Answer

5.39 m/s²

Answer

2 m/s²

Answer

10 m/s²

Answer

7 m/s²

Question 20

Streamlines and pathlines are two concepts used to describe the motion of fluid particles. What is the key difference between them?

Accepted Answer

Streamlines show the instantaneous velocity of a fluid particle, while pathlines show the path of a specific fluid particle over time.

Answer

Streamlines are always straight lines, while pathlines can be curved.

Answer

Streamlines are only applicable to laminar flow, while pathlines can be used for both laminar and turbulent flow.

Answer

Pathlines are always tangent to streamlines at any given point.

Question 21

The continuity equation is a fundamental principle in fluid mechanics. Which of the following is the correct mathematical form of the continuity equation for an incompressible fluid?

Accepted Answer

∇ · V = 0

Answer

∇ · V = 1

Answer

∇² · V = 0

Answer

∇³ · V = 0

Question 22

Potential flow is a type of fluid flow that has certain special characteristics. Which of the following is a characteristic of potential flow?

Accepted Answer

Irrotational

Answer

Viscous

Answer

Compressible

Answer

Turbulent

Question 23

The Bernoulli equation is a powerful tool for analyzing fluid flow. Under which conditions is the Bernoulli equation applicable?

Accepted Answer

Inviscid, incompressible, irrotational flow

Answer

Inviscid, compressible, rotational flow

Answer

Viscous, compressible, rotational flow

Answer

Viscous, incompressible, rotational flow

Question 24

Vorticity is a measure of the local rotation of a fluid element. What is the mathematical definition of vorticity?

Accepted Answer

Vorticity = (∇ x V)

Answer

Vorticity = (∇² · V)

Answer

Vorticity = (∇³ · V)

Answer

Vorticity = (∇ · V)