Isentropic Flow Analysis: A Comprehensive Guide for Fluid Mechanics Students

Question 1

Which of the following is the isentropic relation for pressure?

Accepted Answer

p/p_0 = (1 + (k - 1) / 2 * M^2)^(k / (k - 1))

Answer

p/p_0 = (1 - (k - 1) / 2 * M^2)^(k / (k - 1))

Question 2

At what Mach number does a normal shock wave occur?

Accepted Answer

M > 1

Answer

M < 1

Answer

M = 1

Question 3

Which of the following characterizes isentropic flow?

Accepted Answer

Constant entropy

Answer

Constant pressure

Answer

Constant temperature

Question 4

What happens to the density of a fluid after passing through a normal shock wave?

Accepted Answer

It increases

Answer

It decreases

Question 5

What is the Rankine-Hugoniot relation for velocity across a normal shock wave?

Accepted Answer

v_2 = v_1 * M_1 / (1 + (k - 1) / 2 * M_1^2)

Answer

v_2 = v_1 * (1 + (k-1)/2 * M_1^2)/M_1

Question 6

Which of the following equations represents the conservation of mass for an isentropic flow?

Accepted Answer

ρ₁ A₁ V₁ = ρ₂ A₂ V₂

Answer

ρ₁ V₁ = ρ₂ V₂

Answer

ρ₁ A₁ V₁γ = ρ₂ A₂ V₂γ

Answer

ρ₁ V₁γ = ρ₂ V₂γ

Question 7

Which of the following is NOT an isentropic relation?

Accepted Answer

P₁ V₁γ = P₂ V₂γ

Answer

P₁ρ₁γ = P₂ρ₂γ

Answer

T₁ρ₁γ = T₂ρ₂γ

Answer

ρ₁ V₁²)γ = ρ₂ V₂²)γ

Question 8

Define Mach number.

Accepted Answer

The ratio of flow velocity to sound speed

Answer

The ratio of pressure to density

Answer

The ratio of temperature to entropy

Answer

The ratio of viscosity to density

Question 9

What is the primary purpose of a normal shock wave in isentropic flow?

Accepted Answer

To decrease velocity and increase pressure

Answer

To increase velocity and decrease pressure

Answer

To increase entropy and create turbulence

Answer

To conserve mass and energy

Question 10

Which condition is NOT required for isentropic flow?

Accepted Answer

Steady

Answer

Adiabatic

Answer

Reversible

Answer

Irrotational

Question 11

How is isentropic flow related to entropy?

Accepted Answer

Isentropic flow has constant entropy

Answer

Isentropic flow has decreasing entropy

Answer

Isentropic flow has increasing entropy

Answer

Isentropic flow is not related to entropy

Question 12

What is the Mach number of a flow where the local velocity is equal to the speed of sound?

Accepted Answer

1

Answer

Less than 1

Answer

0

Answer

Greater than 1

Question 13

Which of the following statements about isentropic flow is true?

Accepted Answer

Entropy remains constant throughout the flow.

Answer

Pressure remains constant throughout the flow.

Answer

Temperature remains constant throughout the flow.

Answer

Velocity remains constant throughout the flow.

Question 14

Which of the following best describes an isentropic process?

Accepted Answer

A process with constant entropy

Answer

A process with constant enthalpy

Answer

A process with constant temperature

Answer

A process with constant volume

Question 15

The Mach number (M) is defined as the ratio of:

Accepted Answer

Flow velocity to the speed of sound

Answer

Flow velocity to the critical velocity

Answer

Speed of sound to the flow velocity

Answer

Critical velocity to the flow velocity

Question 16

Which of the following is NOT a characteristic of supersonic flow?

Accepted Answer

Flow is laminar

Answer

Shock waves can form

Answer

Flow velocity is greater than the speed of sound

Answer

Flow is compressible

Question 17

A major limitation of the isentropic flow assumption is that:

Accepted Answer

It does not account for irreversibilities in the flow

Answer

It requires the flow to be steady

Answer

It is only applicable to inviscid flows

Answer

It assumes the flow is incompressible

Question 18

In a diverging nozzle, the flow velocity:

Accepted Answer

Increases

Answer

Remains constant

Answer

Decreases

Question 19

The defining characteristic of an isentropic flow is that:

Accepted Answer

Its entropy remains constant

Answer

Its velocity remains constant

Answer

Its temperature remains constant

Answer

Its pressure remains constant