Numerical simulation of the effect of different divergent angle of pylon

Scramjet engine is regarded as the future for reusable launch vehicles and high-speed transportation, nonetheless, the mixing and combustion of fuel present a difficulty at supersonic speeds. The supersonic velocity reduces the time available for the proper mixing of air and fuel. Researchers have noted that positioning a pylon before the cavity improves the efficiency of mixing. However, the impact of the pylon on the downstream region of the cavity remains unexplored. To address this gap, the current study investigates the consequences of fuel injection when a pylon is placed downstream of the cavity, exploring different divergent angles of the pylon to understand the impact of the pylon. Numerical simulation is employed, utilizing a hybrid RANS/LES simulation with an enhanced delayed detached eddy simulation (IDDES) turbulence model. The study reveals that the downstream placement of the pylon, in combination with different divergent angles, significantly influences the efficiency of mixing and the penetration height. To gain a deeper understanding of the mixing dynamics, additional investigation using dynamic mode decomposition (DMD) has been performed.