Inertia loading in unsteady flow

Question 1

What is the most important example of unsteady fluid loading?

Answer 1

Loading due to waves, where the velocity components are time-dependent.

Question 2

In wave-induced loading, the velocity u⃗ = (u(x, z, t), w(x, z, t)) is a function of _______.

Answer 2

time

Question 3

True or False: The pressure distribution is symmetric in unsteady flow.

Answer 3

False – symmetry breaks due to the unsteady term.

Question 4

Why is the symmetric pressure term neglected when computing net force?

Answer 4

Because its integral around the full surface of the cylinder equals zero.

Question 5

What is the simplified expression for inertia force per unit length?

Answer 5

Fₓ = (1/2)·π·ρ·D²·(∂U/∂t)

Question 6

In the inertia force expression, Fₓ has units of force per unit _____.

Answer 6

length

Question 7

What is the inertia coefficient
Cm and when is it introduced?

Answer 7

A correction factor used to account for flow separation in real (viscous) conditions.

Question 8

What causes the inertia force in unsteady flow?

Answer 8

A net force acting on accelerating fluid particles, which is transferred to a structure.

Question 9

In potential flow theory, the inertia force does not involve ________.

Answer 9

viscous separation

Question 10

True or False: Inertia force is the same as drag force.

Answer 10

False – it acts due to acceleration, not velocity.

Question 11

What is the empirically corrected inertia force expression?

Answer 11

Fₓ = Cₘ · (1/2)·π·ρ·D²·(∂U/∂t)