In nuclear safety systems, both small modular reactors and pressurized water reactors employed submerged jet methods to directly inject high-temperature, high-pressure gas into subcooled water, achieving rapid cooling and depressurization to ensure the effectiveness of reactor safety systems. This study investigated the dynamic behavior of non-condensable air jets in pressurized containment systems, focusing on pressure oscillations and bubble morphology under varying conditions. Using Computational Fluid Dynamics (CFD) simulations with the k − ε turbulence model and Volume of Fluid (VOF) approach, the gas–liquid interactions were modeled and validated against PPOOLEX experimental results, showing high consistency in bubble morphology predictions. The results revealed that jet momentum and mass flow rate significantly influence pressure oscillations and bubble dynamics. At lower flow rates, periodic oscillations and symmetric bubble formations dominate, while higher flow rates led to irregular pressure variations and asymmetric bubble morphologies. Fast Fourier Transform (FFT) analysis demonstrated that velocity oscillation amplitudes increase substantially more than frequencies with higher mass flow rates. Additionally, the interaction of high-temperature jets with subcooled water caused localized thermal disturbances and elevated pressures in the gas space. These findings enhanced understanding of the coupling between pressure, velocity, and temperature fields, offering valuable insights for optimizing pressurized containment systems to ensure safety and reliability during operational and accident scenarios.