Passive Control of Base Flow at Supersonic Mach Number for Area Ratio 4

This paper presents simulation results to assess a cavity's impact on base pressure at a supersonic Mach number of 1.4. The flow field in a sudden expansion flow is disrupted due to the presence of a cavity to control the base pressure and reduce base drag. This study also focuses on understanding the recirculation region's flow pattern and the flow's behavior through a converging–diverging nozzle. C-D nozzles are used in many aerospace industries. This research is carried out by the numerical approach using Computational Fluid Dynamics (CFD) Analysis. The simulation part, considering the Mach number, area ratio of 4, and the nozzle pressure ratio in the range of 2 to 10, was gathered at various length-to-diameter (L/D) ratios and cavity aspect ratios when conducting this analysis. The cavity aspect ratio used in this research is 3:3, 3:6, 6:3, and 6:6, which will show the results of the base pressure. Throughout this investigation, the cavity is located at 1D. The work applied the K-standard wall function turbulence model with the commercial computational fluid dynamics (CFD) and verified it. The C-D nozzle was created and modeled. The results demonstrate that the expansion level (Nozzle Pressure Ratio), the cavity aspect ratio, and the cavity's location significantly influenced the base pressure.