FLUID MECHANICS – ORIGINAL PRACTICE BANK (500+ PAGES TARGET)
Fluid Mechanics
Original Practice Problem Bank – Expanded Edition
1760 Exam-Style Questions with Detailed Rationales
All major undergraduate topics • Original content only
Introduction • Hydrostatics • Control Volume • Differential Form • Dimensional Analysis • Pipe Flow • External Flow • Potential Flow
• Compressible Flow • Open Channels • Turbomachinery
CRITICAL DISCLAIMER – This document contains ONLY original practice questions and rationales written independently for educational review. It is NOT a
reproduction, transcription, or derivative of the problems or solutions appearing in Frank M. White’s Fluid Mechanics or any commercial solutions manual.
Copyrighted textbook material cannot be supplied. Always use your official course textbook as the primary reference.
Section Mapping
# Topic Range N
1 Chapter 1 – Introduction & Basic Concepts Q1-160 160
2 Chapter 2 – Pressure Distribution & Hydrostatics Q161-320 160
3 Chapter 3 – Integral Relations for a Control Vol Q321-480 160
4 Chapter 4 – Differential Relations for Fluid Flo Q481-640 160
5 Chapter 5 – Dimensional Analysis & Similarity Q641-800 160
6 Chapter 6 – Viscous Flow in Ducts Q801-960 160
7 Chapter 7 – Flow Past Immersed Bodies Q961-1120 160
8 Chapter 8 – Potential Flow Q1121-1280 160
9 Chapter 9 – Compressible Flow Q1281-1440 160
10 Chapter 10 – Open-Channel Flow Q1441-1600 160
11 Chapter 11 – Turbomachinery Q1601-1760 160
TOTAL 1760
Original Problems & Solutions | Page 1
, FLUID MECHANICS – ORIGINAL PRACTICE BANK (500+ PAGES TARGET)
Section 1: Chapter 1 – Introduction & Basic Concepts
Q1: The continuum assumption in fluid mechanics means that:
A. Fluids are treated as discrete molecules at all scales
B. Macroscopic properties are treated as continuous functions of space and time [CORRECT]
C. Only ideal gases exist
D. Viscosity is always zero
Correct Answer: B
Rationale: The continuum hypothesis allows density, velocity, pressure and other field variables to be defined
as continuous functions of position and time. It is valid when the mean free path is much smaller than the
macroscopic length scale of interest (Knudsen number << 1).
Q2: A Newtonian fluid is one for which:
A. Shear stress is independent of strain rate
B. Shear stress is linearly proportional to the rate of strain [CORRECT]
C. Density changes with pressure only
D. Viscosity is infinite
Correct Answer: B
Rationale: For a Newtonian fluid the viscous stress tensor is a linear function of the strain-rate tensor. The
constant of proportionality is the dynamic viscosity µ. Water, air and most common fluids are Newtonian under
ordinary conditions.
Q3: Dynamic viscosity µ has dimensions of:
A. M L−1 T−1 [CORRECT]
B. M L−1 T−2
C. L2 T−1
D. M L T−1
Correct Answer: A
Rationale: From Newton’s law of viscosity τ = µ (du/dy), stress has dimensions M L−1 T−2 and velocity
gradient has dimensions T−1, so µ has dimensions M L−1 T−1 (Pa·s in SI).
Original Problems & Solutions | Page 2
, FLUID MECHANICS – ORIGINAL PRACTICE BANK (500+ PAGES TARGET)
Q4: Kinematic viscosity ν is defined as:
A. µ × ρ
B. µ / ρ [CORRECT]
C. ρ / µ
D. µ2 / ρ
Correct Answer: B
Rationale: Kinematic viscosity ν = µ/ρ removes density from the viscous coefficient and has dimensions L2
T−1. It appears naturally in the Reynolds number and in the diffusion of momentum.
Q5: Surface tension σ has dimensions of:
A. Force per unit length (or energy per unit area) [CORRECT]
B. Force per unit area only
C. Mass per unit volume
D. Velocity squared
Correct Answer: A
Rationale: Surface tension is a force per unit length (N/m) or equivalently an energy per unit area (J/m2). It is
responsible for capillary rise, droplet formation and the capillary pressure jump given by the Young–Laplace
equation.
Q6: The no-slip condition at a solid wall states that:
A. Fluid velocity is always zero everywhere
B. The fluid velocity relative to the wall is zero at the wall (continuum regime) [CORRECT]
C. Pressure is zero at the wall
D. Viscosity vanishes at the wall
Correct Answer: B
Rationale: In the continuum regime the tangential and normal velocity components of the fluid match those of
the solid surface. This empirical boundary condition is essential for viscous-flow theory.
Original Problems & Solutions | Page 3
, FLUID MECHANICS – ORIGINAL PRACTICE BANK (500+ PAGES TARGET)
Q7: Specific gravity of a fluid is:
A. Absolute density in kg/m3
B. Ratio of its density to the density of a reference fluid (usually water at 4 °C) [CORRECT]
C. Viscosity divided by density
D. Pressure divided by density
Correct Answer: B
Rationale: Specific gravity SG = ρ/ρ_ref is dimensionless and convenient for comparing densities. For liquids
the reference is ordinarily liquid water.
Q8: Bulk modulus of a fluid measures:
A. Resistance to shear
B. Resistance to volumetric compression (inverse of compressibility) [CORRECT]
C. Surface tension
D. Thermal conductivity
Correct Answer: B
Rationale: Bulk modulus K = −dp/(d∀/∀) quantifies how much pressure is needed to produce a relative
change in volume. Large K implies nearly incompressible behaviour.
Q9: (Practice set item 9) The continuum assumption in fluid mechanics means that:
A. Fluids are treated as discrete molecules at all scales
B. Macroscopic properties are treated as continuous functions of space and time [CORRECT]
C. Only ideal gases exist
D. Viscosity is always zero
Correct Answer: B
Rationale: The continuum hypothesis allows density, velocity, pressure and other field variables to be defined
as continuous functions of position and time. It is valid when the mean free path is much smaller than the
macroscopic length scale of interest (Knudsen number << 1).
Original Problems & Solutions | Page 4
Fluid Mechanics
Original Practice Problem Bank – Expanded Edition
1760 Exam-Style Questions with Detailed Rationales
All major undergraduate topics • Original content only
Introduction • Hydrostatics • Control Volume • Differential Form • Dimensional Analysis • Pipe Flow • External Flow • Potential Flow
• Compressible Flow • Open Channels • Turbomachinery
CRITICAL DISCLAIMER – This document contains ONLY original practice questions and rationales written independently for educational review. It is NOT a
reproduction, transcription, or derivative of the problems or solutions appearing in Frank M. White’s Fluid Mechanics or any commercial solutions manual.
Copyrighted textbook material cannot be supplied. Always use your official course textbook as the primary reference.
Section Mapping
# Topic Range N
1 Chapter 1 – Introduction & Basic Concepts Q1-160 160
2 Chapter 2 – Pressure Distribution & Hydrostatics Q161-320 160
3 Chapter 3 – Integral Relations for a Control Vol Q321-480 160
4 Chapter 4 – Differential Relations for Fluid Flo Q481-640 160
5 Chapter 5 – Dimensional Analysis & Similarity Q641-800 160
6 Chapter 6 – Viscous Flow in Ducts Q801-960 160
7 Chapter 7 – Flow Past Immersed Bodies Q961-1120 160
8 Chapter 8 – Potential Flow Q1121-1280 160
9 Chapter 9 – Compressible Flow Q1281-1440 160
10 Chapter 10 – Open-Channel Flow Q1441-1600 160
11 Chapter 11 – Turbomachinery Q1601-1760 160
TOTAL 1760
Original Problems & Solutions | Page 1
, FLUID MECHANICS – ORIGINAL PRACTICE BANK (500+ PAGES TARGET)
Section 1: Chapter 1 – Introduction & Basic Concepts
Q1: The continuum assumption in fluid mechanics means that:
A. Fluids are treated as discrete molecules at all scales
B. Macroscopic properties are treated as continuous functions of space and time [CORRECT]
C. Only ideal gases exist
D. Viscosity is always zero
Correct Answer: B
Rationale: The continuum hypothesis allows density, velocity, pressure and other field variables to be defined
as continuous functions of position and time. It is valid when the mean free path is much smaller than the
macroscopic length scale of interest (Knudsen number << 1).
Q2: A Newtonian fluid is one for which:
A. Shear stress is independent of strain rate
B. Shear stress is linearly proportional to the rate of strain [CORRECT]
C. Density changes with pressure only
D. Viscosity is infinite
Correct Answer: B
Rationale: For a Newtonian fluid the viscous stress tensor is a linear function of the strain-rate tensor. The
constant of proportionality is the dynamic viscosity µ. Water, air and most common fluids are Newtonian under
ordinary conditions.
Q3: Dynamic viscosity µ has dimensions of:
A. M L−1 T−1 [CORRECT]
B. M L−1 T−2
C. L2 T−1
D. M L T−1
Correct Answer: A
Rationale: From Newton’s law of viscosity τ = µ (du/dy), stress has dimensions M L−1 T−2 and velocity
gradient has dimensions T−1, so µ has dimensions M L−1 T−1 (Pa·s in SI).
Original Problems & Solutions | Page 2
, FLUID MECHANICS – ORIGINAL PRACTICE BANK (500+ PAGES TARGET)
Q4: Kinematic viscosity ν is defined as:
A. µ × ρ
B. µ / ρ [CORRECT]
C. ρ / µ
D. µ2 / ρ
Correct Answer: B
Rationale: Kinematic viscosity ν = µ/ρ removes density from the viscous coefficient and has dimensions L2
T−1. It appears naturally in the Reynolds number and in the diffusion of momentum.
Q5: Surface tension σ has dimensions of:
A. Force per unit length (or energy per unit area) [CORRECT]
B. Force per unit area only
C. Mass per unit volume
D. Velocity squared
Correct Answer: A
Rationale: Surface tension is a force per unit length (N/m) or equivalently an energy per unit area (J/m2). It is
responsible for capillary rise, droplet formation and the capillary pressure jump given by the Young–Laplace
equation.
Q6: The no-slip condition at a solid wall states that:
A. Fluid velocity is always zero everywhere
B. The fluid velocity relative to the wall is zero at the wall (continuum regime) [CORRECT]
C. Pressure is zero at the wall
D. Viscosity vanishes at the wall
Correct Answer: B
Rationale: In the continuum regime the tangential and normal velocity components of the fluid match those of
the solid surface. This empirical boundary condition is essential for viscous-flow theory.
Original Problems & Solutions | Page 3
, FLUID MECHANICS – ORIGINAL PRACTICE BANK (500+ PAGES TARGET)
Q7: Specific gravity of a fluid is:
A. Absolute density in kg/m3
B. Ratio of its density to the density of a reference fluid (usually water at 4 °C) [CORRECT]
C. Viscosity divided by density
D. Pressure divided by density
Correct Answer: B
Rationale: Specific gravity SG = ρ/ρ_ref is dimensionless and convenient for comparing densities. For liquids
the reference is ordinarily liquid water.
Q8: Bulk modulus of a fluid measures:
A. Resistance to shear
B. Resistance to volumetric compression (inverse of compressibility) [CORRECT]
C. Surface tension
D. Thermal conductivity
Correct Answer: B
Rationale: Bulk modulus K = −dp/(d∀/∀) quantifies how much pressure is needed to produce a relative
change in volume. Large K implies nearly incompressible behaviour.
Q9: (Practice set item 9) The continuum assumption in fluid mechanics means that:
A. Fluids are treated as discrete molecules at all scales
B. Macroscopic properties are treated as continuous functions of space and time [CORRECT]
C. Only ideal gases exist
D. Viscosity is always zero
Correct Answer: B
Rationale: The continuum hypothesis allows density, velocity, pressure and other field variables to be defined
as continuous functions of position and time. It is valid when the mean free path is much smaller than the
macroscopic length scale of interest (Knudsen number << 1).
Original Problems & Solutions | Page 4
