could a wave go faster than the sound barrier if the wave underwent a phase change

[jpmurphy]

I was looking at a wikipedia page about the sound barrier, and thought a question that there was no answer to in the page. If you had a liquid that was about to be a solid if you put a little more presure. then you set an explosion would the resulting wave be able to go faster than the sound barrier? The equations don't account for phase changes. Something really interesting to try is to see if you can have a liquid close to being a solid with a little more pressure, and set it up to take the pressure away afterward. Could you do this with air?

[arc]

You may be able to show this effect using a non-Newtonian fluid in a chamber of some kind. A long tube filled with the non-Newtonian liquid with pressure sensors at both ends and a simple speaker on one end. By adjusting the output you should find that phase change and deduct the liquid phase wave speed. But can you differentiate in some way a second stronger pulse that could travel in the solid phase?

[Enthalpy]

A strong pressure wave goes faster than sound, whose velocity is computed by assuming a small pressure variation. Shock waves made by explosions in air travel faster than sound. So experimentally, the phase change demands a strong pressure variation, but this alone may create a faster wave, making the interpretation more difficult.

 

If a stronger is to pressure freeze the liquid, the liquid must contract upon freezing - what most materials do, water being abnormal. I expect this behaviour to slow down the wave, as it makes the material less stiff: a pressure variation would make a stronger volume variation due to freezing.

 

As reversible freezing means much heat, pressure would probably freeze only a part of the material, but this changes only the figures, not the concept.