Normal Shock Waves topics include: Normal shock equations, flow compressible and its velocity measurement. A normal shock wave is a one-dimensional flow configuration that can be used to study flow behavior and transport processes.  A normal shock wave is a shock with a wave front that is perpendicular to the freestream flow. They occur in supersonic internal and jet flows.  A normal shock wave is the most fundamental type of shock. It is a traveling wave that moves relative to the fluid faster than the local speed of sound.  Here are some characteristics of normal shock waves: Shock... Show more

Normal Shock Waves topics include: Normal shock equations, flow compressible and its velocity measurement.

A normal shock wave is a one-dimensional flow configuration that can be used to study flow behavior and transport processes. 

A normal shock wave is a shock with a wave front that is perpendicular to the freestream flow. They occur in supersonic internal and jet flows. 
A normal shock wave is the most fundamental type of shock. It is a traveling wave that moves relative to the fluid faster than the local speed of sound. 

Here are some characteristics of normal shock waves:
Shock waves are very thin
Shock waves are highly localized irreversibilities in the flow

As fluid passes through a shock wave, pressure, temperature, and density will increase; velocity will decrease:
Within the distance of a mean free path, the flow passes from a supersonic to a subsonic state, the velocity decreases suddenly and the pressure rises sharply 
Shock waves are typically very thin, with thicknesses on the order of 1 µm. 

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Aerodynamics Practice Test: Normal Shock Waves

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25 Questions

1. Which is not true for continuity equation of normal shock?

ρ1u1=ρ2u2Steady flowρ1u1A1=ρ2u2A2No viscosity

2. The equation a=-ρ\(\frac {da}{d\rho }\) where a is the speed of sound in the medium is the mathematical expression derived for the sound waves, which are _________

ReversibleIncompressibleIsentropicAdiabatic

3. Select the false statement for the normal shock wave.

Entropy increases across normal shock waveNormal shock wave is a compression waveThe total temperature remains constantThe total pressure remains constant

4. Specifying the temperature ratio across the normal shock wave will yield which of the following across the normal shock wave?

Upstream Mach numberUpstream flow velocityDownstream flow velocityDownstream temperature

5. Shock waves can occur both in subsonic and supersonic medium since the concerning equations are not concerned with whether M > 1 or M < 1.

MaybeTrueFalseDon't Know

6. For compressible flow also, we can calculate velocity with the Pitot and static pressure found.

TrueMaybeDon't KnowFalse

7. .The properties of a flow with subscript * denotes M=1. Which of these is the correct ratio for a flow with gamma= 1.4?"

\(\frac {T^*}{T_0}\)=0.528\(\frac {P^*}{P_0}\)=0.833Data inadequate\(\frac {\rho ^*}{\rho_0}\)=0.634

8. Select the incorrect statement out of the following.

Incompressible flow is theoretically zero-Mach number flowsSpeed of sound in incompressible medium is zerolimτs→0⁡ is the case of an incompressible flowMach number for finite velocity object, in incompressible flow is zero

9. The speed of sound in any medium is a function of_____

T, ρP, ρP, TT only

10. A shock wave that is normal to the upstream flow is a rare case.

TrueFalseMaybeDon't Know

11. Select the false statement for the normal shock wave.

Thermal and frictional dissipation thereShock wave is pretty thickEntropy increases across normal shock waveNormal shock wave has velocity and pressure gradients

12. The definition of stagnation pressure can help us calculate the velocity of sound for an incompressible flow. What else do we need for the calculation?

Static velocityStatic pressureTotal pressureAmbient temperature

13. Select the correct statement for a Mach wave.

\(\frac {P_2}{P_1}\)=0.528\(\frac {T_2}{T_1}\)=1M > 1\(\frac {\rho_2}{\rho_1}\)=∞

14. The most important quantity that dominates the physical properties of compressible flow is _______

Distance of propagationSpeed of lightSpeed of soundDensity of medium of propagation

15. The isentropic compressibility, in terms of speed of sound in any medium is given by ________

τs=\(\frac {1}{\rho a}\) τs=\(\frac {\rho }{a^2}\) τs=ρa2τs=\(\frac {1}{\rho a^2}\)

16. Mach number is a measure of the directed motion of the gas compared with the random thermal motion of the molecules.

Don't KnowFalseMaybeTrue

17. The supersonic flow over a blunt body is given. Mark the area where the normal shock wave exists.

iiiiiiiv

18. A normal shock wave can be specified with a single velocity.

FalseMaybeDon't knowTrue

19. The total temperature across the normal shock wave is constant. Which statement gives the wrong reason for this?

Adiabatic flow across normal shock waveNormal shock wave has an isentropic flowCalorifically perfect gasThermal dissipation there

20. For subsonic compressible flow, which of these is not required to be measured separately to find the velocity of flow?

Mach numberStagnation pressureStatic pressureFree-stream of sound

21. The incorrect equation for the normal shock equation is_______

ρ1u1=ρ2u2h1+\(\frac {u_1^2}{2}\)=h2+\(\frac {u_2^2}{2}\) p1+ρ1u\(_1^2\)=p2+ρ2u\(_2^2\) ∇.v=0

22. The incorrect relation for properties associated with the flow, for a point in the flow where the speed of sound is a, is_______

\(\frac {\gamma +1}{2(\gamma -1)}\) a*2=\(\frac {a_0^2}{\gamma -1}\)≠const\(\frac {\gamma +1}{2(\gamma -1)}\) a*2=const\(\frac {a_0^2}{\gamma -1}\)=const\(\frac {\gamma +1}{2(\gamma -1)}\) a*2=\(\frac {a_0^2}{\gamma -1}\)=const

23. For a non-perfect gas, if we double the pressure while keeping the temperature same, the speed of sound remains the same.

FalseMaybeDon't KnowTrue

24. Prandtl relation for normal shock waves is_______

a2=u1u2a*a0=u1u2a*2=u1u2a\(_0^2\)=u1u2

25. Prandtl relation can also be expressed in terms of characteristic Mach number as 1=M\(_1^*\)M\(_2^*\).

MaybeTrueFalseDon't know