EIT Fluid Mechanics 1

Question 1

What does Bernoulli's equation express?

Accepted Answer

Conservation of energy along a streamline

Answer

Bernoulli's equation expresses conservation of energy along a streamline: P + ½ρv² + ρgh = constant.

Question 2

The Reynolds number Re = ρvD/μ classifies flow as turbulent when Re exceeds approximately:

Accepted Answer

2300

Answer

Flow in a pipe transitions from laminar to turbulent when Re exceeds approximately 2300.

Question 3

What is the SI unit of dynamic viscosity?

Accepted Answer

Pa·s

Answer

Dynamic viscosity μ has SI units of Pascal-seconds (Pa·s), equivalent to N·s/m².

Question 4

For a fluid at rest, pressure varies with depth according to:

Accepted Answer

P = ρgh

Answer

In a static fluid, pressure increases with depth as P = ρgh, where h is depth below the free surface.

Question 5

The continuity equation for incompressible flow states:

Accepted Answer

A₁v₁ = A₂v₂

Answer

For incompressible flow, the continuity equation simplifies to A₁v₁ = A₂v₂ (conservation of volume flow rate).

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