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Fluid Mechanics Midterm Solutions
Questions and Correct Answers/ Latest
Update / Already Graded
Wall layer
Ans: Laminar shear stress dominated near wall
Fluid
Ans: A substance that deforms continuously under shear
stress. Solid can resist a shear force by a static deformation
(without moving). Fluids cannot resist a shear force, always
moves even with smallest shear.
No-Slip boundary condition
Ans: Flow velocity relative to the boundary is zero.
Slip boundary condition
Ans: Relative speed between fluid and boundary with no
penetration.
Center of pressure
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Ans: Point where hydrostatic force actually acts, lower than
CG.
Assumptions for Bernoulli's equation
Ans: Steady flow, incompressible flow, inviscid flow, fluid acts
along a streamline.
Body Forces
Ans: Forces that act throughout the volume of a body (e.g.,
gravity).
Surface Forces
Ans: Forces that act on fluid elements across a surface (e.g.,
pressure forces, viscous forces).
Matter's 2 states
Ans: Solid and fluid(liquid and gas)
Normal forces
Ans: Pressure or compressive forces
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Tangential forces
Ans: Shear force
Fluid density, 𝜌 (rho)
Ans: Mass per unit volume. 𝜌 = m/v
Principle of Dimensional Homogeneity
Ans: Each additive term in an equation must have the same
dimension.
Liquid vs solid
Ans: Liquids can have a free surface, gasses cannot -> they
tend to expand to fill available volume.
Continuum Approximation
Ans: Treats material as having a continuous distribution of
mass.
4 primary dimensions
All rights reserved © 2025/ 2026 |
Fluid Mechanics Midterm Solutions
Questions and Correct Answers/ Latest
Update / Already Graded
Wall layer
Ans: Laminar shear stress dominated near wall
Fluid
Ans: A substance that deforms continuously under shear
stress. Solid can resist a shear force by a static deformation
(without moving). Fluids cannot resist a shear force, always
moves even with smallest shear.
No-Slip boundary condition
Ans: Flow velocity relative to the boundary is zero.
Slip boundary condition
Ans: Relative speed between fluid and boundary with no
penetration.
Center of pressure
All rights reserved © 2025/ 2026 |
, Page |2
Ans: Point where hydrostatic force actually acts, lower than
CG.
Assumptions for Bernoulli's equation
Ans: Steady flow, incompressible flow, inviscid flow, fluid acts
along a streamline.
Body Forces
Ans: Forces that act throughout the volume of a body (e.g.,
gravity).
Surface Forces
Ans: Forces that act on fluid elements across a surface (e.g.,
pressure forces, viscous forces).
Matter's 2 states
Ans: Solid and fluid(liquid and gas)
Normal forces
Ans: Pressure or compressive forces
All rights reserved © 2025/ 2026 |
, Page |3
Tangential forces
Ans: Shear force
Fluid density, 𝜌 (rho)
Ans: Mass per unit volume. 𝜌 = m/v
Principle of Dimensional Homogeneity
Ans: Each additive term in an equation must have the same
dimension.
Liquid vs solid
Ans: Liquids can have a free surface, gasses cannot -> they
tend to expand to fill available volume.
Continuum Approximation
Ans: Treats material as having a continuous distribution of
mass.
4 primary dimensions
All rights reserved © 2025/ 2026 |
