Revisiting wall heating

The results of computing a shock reflection are found to strongly depend on the chosen coordinate system, Lagrangian or Eulerian. This is seen by comp aring the amount of "wall heating" associated with the solutions to Noh's s hock reflection problem computed in each reference frame. Here, an explanat ion is offered that places a greater burden on the role of phase error or e ffective wave speed in producing this effect. The reason for the greater di fficulties in the Lagrangian frame are the non-uniformity of the mass coord inates in a converging geometry. This produces a non-steady-state discrete shock profile.