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sorry for bothering with my question.

https://en.wikipedia.org/wiki/Sod_shock_tube

I have trying to understand, how is it possible to have a discontinuity on Density and not on Pressure. I don't understand, since we have a Pressure AND a Density discontinuity on t=0 , how can the equilibrium of the Pressure take place Immediate? I understand the Shock the rarefaction but the contact discontinuity bothers me a lot for some days and can't find anything related on Google.

Probably it's a stupid question, but still.. didn't know any other place to ask

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  • $\begingroup$ I think there is a typo in your expressions for pressure and density near the top. Both currently have a subscript of 2. $\endgroup$ – honeste_vivere Apr 11 '17 at 18:57
  • $\begingroup$ Can you normalize the density and pressure plots to the ambient/upstream values or at least show them on a log-linear scale? It's impossible to tell the relative strength of each density discontinuity from these plots. $\endgroup$ – honeste_vivere Apr 11 '17 at 19:36
  • $\begingroup$ @honeste_vivere I fixed it! I had some wrong plots. Is it clear now? It's clear that there are 2 discntinuities on density and one on pressure $\endgroup$ – Billy Matlock Apr 11 '17 at 22:16
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    $\begingroup$ This is often called the Sod Shock Tube, and here are some good references. I can write a more complete answer later, but in short there is only one pressure discontinuity because there is only one surface traveling faster than the local speed of sound---thus preventing the discontinuity from smoothing out. $\endgroup$ – DilithiumMatrix Apr 11 '17 at 23:30
  • $\begingroup$ @DilithiumMatrix Sweat, I ll read them both. I still dont get the Discontinuity on density, but I ll study it more and hopefully I will $\endgroup$ – Billy Matlock Apr 12 '17 at 10:35

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