High temperature effects in moving shock reflection with protruding Mach stem

- Protrusion of Mach stem is induced by a wall-jet behind it.
- High temperature effects intensify Mach stem protrusion.
- The mechanism is increase of energy buffer enhances wall-jet but weakens Mach stem.

The influence of high temperature effects on the protrusion of Mach stem in strong shock reflection over a wedge was numerically investigated. A two-dimensional inviscid solver applies finite volume method and unstructured quadrilateral grids were employed to simulate the flow. Theoretical analysis was also conducted to understand the phenomenon. Both numerical and theoretical results indicate a wall-jet penetrating forward is responsible for the occurrence of Mach stem protrusion. The protrusion degree seems to depend on the thermal energy buffer capacity of the testing gas. Approaches to increase the energy buffer capacity, such as vibrational relaxation, molecular dissociation, and increase of frozen heat capacity, all tend to escalate the protrusion effect.