Shock interactions and heating predictions on a V-shaped blunt leading edge at Mach 6-12

V-shaped blunt leading edges (VSBLEs) are usually found at the inlet lips of air-breathing hypersonic vehicles and irregular shape flows. In this work, the VSBLE flows are investigated using numerical simulations and theoretical analysis from Mach 6 to Mach 12. The simulation results show that complex shock-shock interactions around the VSBLE cause extremely high heat flux peaks, which nonlinearly increase with the freestream Mach numbers. To theoretically study the flow mechanism, the shock interactions are divided into large-scale primary shock interactions (PSIs) and micro-scale secondary shock interactions (SSIs). The PSIs are constant, but the SSIs experience a transition from Mach reflection to regular reflection with the Mach number increasing. A transition criterion for the SSIs is established by the shock interaction theory. Furthermore, the increase in the heat flux peaks is proved to be caused by the SSI transition. A semi-empirical heat flux prediction method that relates the shock intensity and heat flux amplification is established. Finally, the transition criterion and the heat flux prediction method are verified by simulations at higher Mach numbers and experiments of VSBLEs with different geometric parameters. This paper develops a theoretical analysis approach for quickly predicting the shock interaction types and heat flux peaks of the VSBLEs under a wide range of Mach numbers.