Shock Wave Relativity: Exploring Local Thermodynamic Properties

In summary, the conversation discusses an experiment being conducted on Mars in a supersonic storm, where a small sphere is placed in the flow and a shock wave is observed in a laboratory. The speaker then suggests choosing a different reference frame to extract measurements, where the flow would appear subsonic and no shock wave would be seen. However, the other person explains that the relative speed between the sphere and the gas would still be supersonic in this frame and that the movement of the gas is not a factor in determining the presence of a shock wave. The conversation ends with a reference to the "Star Trek" phrase, "Live long and prosper."
  • #1
Clausius2
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Ok, imagine this experiment:

I am in Mars, inside of a supersonic storm. There is a small sphere standing inside the incident flow, and I am in a laboratory viewing the shock wave caused by the sphere. I have some pressure measurements of the flow, (i.e around of the sphere surfice), so I can demostrate the shock wave presence.

At this point, I have the idea of choosing a different reference frame for extracting measurements. I choose just a reference frame where I can see the flow being completely subsonic (i.e. the laboratory translates at some speed so that viewing is possible, by means of a galilean velocity composition). If the flow is subsonic, no shock wave will be seen at all. I suppose (certainly?) that static pressure and entropy measurements are not a function of the reference frame chosen, so I will have the same experimental figures of the first case, where the flow was supersonic.

I mean, in some reference frame I will see a shock wave, and in another I will not see one. But we know that a fluid throug shock waves have an increasing in its entropy and a strong pressure loss. This two properties are not a function of a reference frame, because are local thermodynamic properties of the flow.

What happens? Is there a shock wave? How could I demostrate that in these two laboratories?
 
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  • #2
I believe you got yourself a bit confused by this one,
happens to me too. :smile:

In a "different" reference frame the relative speed between
your sphere and the gas will still be supersonic and that's
ALL you need to look at. As for the movemnt of the
gas itself - it doesn't matter weather an object moves
through the gas or the gas past the object - on a
windy day you can see that a bird can stay in one
spot or a model airplane can fly very slowly upwind and
very fast downwind - this is because the amount of
lift is constant, and lift depends on RELATIVE motion between
the geometry creating lift - object, and the gas(/liquid).

Live long and prosper.
 
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  • #3
Hi drag,

Probably you are right. So I would see a traveling shock wave.
 

1. What is shock wave relativity?

Shock wave relativity is a branch of physics that studies the behaviors of matter and energy under extreme conditions, such as high speeds or intense pressure. It focuses on how the laws of thermodynamics and relativity apply in these extreme scenarios.

2. How does shock wave relativity relate to local thermodynamic properties?

Shock wave relativity explores how local thermodynamic properties, such as temperature, pressure, and density, change under extreme conditions. It helps us understand how these properties affect the behavior of matter and energy in these conditions.

3. What are some real-world applications of shock wave relativity?

Shock wave relativity has many practical applications, such as in the design of high-speed vehicles like rockets and jets. It also helps us understand the behavior of matter in extreme environments, such as inside stars or during nuclear explosions.

4. How is shock wave relativity different from other branches of physics?

Shock wave relativity is unique in that it combines the principles of thermodynamics and relativity to study extreme conditions. It also focuses specifically on local thermodynamic properties, rather than the overall behavior of matter and energy.

5. What are the current developments and advancements in shock wave relativity?

There are ongoing studies and experiments in shock wave relativity, such as using lasers to create high-speed shock waves in laboratories. Researchers are also using computer simulations to better understand and predict the behavior of matter under extreme conditions.

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