Scramjet is the future of high-speed transportation and reusable launch vehicle for satellite placement. However, the combustion of fuel at a supersonic speed is challenging. Since the combustion occurs at the supersonic velocity, the retention time for the proper mixing of air and fuel is less. The present study focuses on the effect of pylon placed downstream of the cavity to enhance the mixing of air and fuel. Hybrid RANS/LES simulation is conducted using an improved delayed detached eddy simulation (IDDES) turbulence model. The cavity-based combustor is taken as a benchmark to validate the code. The mixing efficiency is highly affected by the downstream placement of the pylon. Further analysis is conducted using dynamic mode decomposition (DMD).