Extend the analysis to vibrationally active nitrogen

Determine whether vibrational relaxation in thermochemically nonequilibrium nitrogen introduces an additional slow collective coordinate or otherwise changes the resolved bow-layer displacement dynamics.

Background

The simulations use a rotationally relaxing nitrogen model without vibrational excitation or chemistry. The estimated post-shock temperature is comparable to nitrogen’s characteristic vibrational temperature, indicating that vibrational energy could be dynamically relevant in the physical flow.

The current conclusions are therefore restricted to the rotational model implemented in DS2V. A vibrationally active calculation is needed to determine whether vibrational relaxation adds a slow mode or modifies the persistence, shape, and moment synchronization of the collective displacement.

References

The perfect-gas temperature estimate above shows that vibration is energetically accessible, so vibrational relaxation could add a slow coordinate in physical nitrogen. The present result must therefore not be generalized to thermochemical nonequilibrium without a vibrationally active calculation.

— Noise-separated evidence for a slow collective displacement in a rarefied hypersonic bow-shock layer  (2608.17285 - Shoja-sani et al., 18 Aug 2026) in Section 4.7, “Limitations and scope of the conclusions”