4.2.4 Jumps in the solution of the Sod shock tube problem

The similarity solution of the Sod shock tube problem contains

• a rarefaction wave going to the left,
• a contact discontinuity travelling slowly to the right,
• a shock wave moving fast to the right.

For the all individual waves the upwind direction is clear.

Only in the (possible) case of a transonic rarefaction wave ``upwind'' is not obvious However, here an entropy fix has to be applied, anyway.