Fundamentals of Engineering Fluid Mechanics and Thermodynamics 3

Question 1

What is the specific heat ratio (γ = Cp/Cv) for a diatomic ideal gas at standard conditions?

Accepted Answer

1.4

Answer

Diatomic gases like air (N₂, O₂) have γ = Cp/Cv ≈ 1.4 at standard conditions.

Question 2

Which dimensionless number characterizes the ratio of convective to conductive heat transfer?

Accepted Answer

Nusselt number

Answer

The Nusselt number Nu = hL/k is the ratio of convective to conductive heat transfer across a boundary.

Question 3

In pipe flow, what Reynolds number approximately marks the transition from laminar to turbulent flow?

Accepted Answer

~2,300

Answer

Flow in a pipe transitions from laminar to turbulent at Re ≈ 2,300; above ~4,000 is fully turbulent.

Question 4

What is the thermodynamic process called when pressure remains constant?

Accepted Answer

Isobaric process

Answer

An isobaric process occurs at constant pressure; work done is W = PΔV.

Question 5

Stagnation pressure in compressible flow is the pressure measured at a point where:

Accepted Answer

The flow velocity is reduced to zero isentropically

Answer

Stagnation (total) pressure is the pressure that would result if the flow were brought to rest isentropically.

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